Method and system for fuel operated heater

Abstract

The invention provides a method and system for a fuel operated heater. Methods and systems are provided for a fuel system. In one example, a method may include adjusting operation of a fuel operated heater (FOH) and an exhaust system to regenerate the FOH. The operations may include flowing gas from the exhaust system to the FOH to return the FOH to a less coked state.

Description

TECHNICAL FIELD

[0001] This specification generally relates to methods and systems for a fuel-operated heater for a vehicle. BACKGROUND

[0002] A vehicle may include a fuel-operated heater (FOH) to provide cabin heating during conditions of engine power loss. The FOH may burn fuel to heat its heat exchanger to heat ambient air. The heated ambient air may flow into the interior of the vehicle cabin.

[0003] Due to the generation of soot particulate matter, the FOH may become fouled. Fouling of the FOH may increase when the vehicle is at a higher altitude (e.g., above 5,000 feet above sea level) because there is less and less oxygen. At higher altitudes, the FOH may experience incomplete combustion, which may increase fouling and reduce its efficiency. Accordingly, methods and systems for cleaning the FOH may be desirable. SUMMARY

[0004] In one example, the above problem may be solved by a system that includes a fuel-operated heater (FOH) fluidly coupled to an exhaust system of an engine. In this way, the exhaust can be used to regenerate the FOK to a less fouled state.

[0005] As an example, a multi-position valve may be positioned in a passage fluidly coupled to an exhaust passage and the FOH. The multi-position valve may be configured to control fresh air and exhaust flow to the FOH. When there is a request for regeneration of the FOH, the multi-position valve may be actuated to a position that allows exhaust to reach a regeneration passage from the exhaust passage. By doing so, hot exhaust can flow to the FOH and burn soot and other contaminants.

[0006] It should be understood that the above Summary is provided to introduce in a simplified form a selection of concepts that are further described in the Detailed Description. This is not meant to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the Detailed Description. Moreover, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Advantages described herein will be more fully understood when the example embodiments referred to as the Detailed Description are read in conjunction with the drawings, in which:

[0008] Figure 1 An advanced block diagram illustrating an example vehicle propulsion system is shown;

[0009] Figure 2 ShowsFigure 1 An example engine system, fuel system, and evaporative emissions control (EVAP) system included in an example vehicle system;

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

[0011] Figure 4 A first method for cleaning the FOH when the engine is burning fuel is shown;

[0012] Figure 5 A second method for cleaning the FOH when the engine is not burning fuel is shown; and

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

[0014] The following description relates to systems and methods for an FOH system for a vehicle. The vehicle can be at least a partially electric vehicle including a pure electric mode. Figure 1 A high-level block diagram illustrating an example vehicle propulsion system is shown. Figure 2 Shown is Figure 1 An example engine system, fuel system, and evaporative emissions control (EVAP) system included in an example vehicle system. Figure 3 An example of a fuel-operated heater (FOH) system coupled to an emissions system of an engine system is shown. Figure 4 A first method for cleaning the FOH when the engine is burning fuel is shown. Figure 5 A second method for cleaning the FOH when the engine is not burning fuel is shown. Figure 6 An operating sequence illustrating the conditions of the FOH system and the exhaust system is shown.

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

[0016] Figure 1 An example 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 may be configured to utilize or consume an energy source different from that of the engine 110. For example, the engine 110 may consume liquid fuel (e.g., gasoline) to produce an engine output, while the motor 120 may consume electrical energy to produce a motor output. Thus, a vehicle having the propulsion system 100 may be referred to as a hybrid electric vehicle (HEV).

[0017] 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 a shut-off state (e.g., set to a deactivated state), where fuel combustion at the engine ceases. 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 can be set to the deactivated state (as described above), and the motor 120 can be operated to charge the energy storage device 150. For example, the motor 120 can receive wheel torque from the drive wheels 130 as indicated by arrow 122, where the motor can convert the vehicle's kinetic energy into electrical energy for storage at the energy storage device 150 as indicated by arrow 124. This operation can be referred to as regenerative energy recovery of the vehicle. Thus, in some embodiments, the motor 120 can provide a generator function. However, in other embodiments, the generator 160 can alternatively receive wheel torque from the drive wheels 130, where the generator can convert the vehicle's kinetic energy into electrical energy for storage at the energy storage device 150 as indicated by arrow 162.

[0019] During still some other operating conditions, the engine 110 can operate by burning fuel received from the fuel system 140 as indicated by arrow 142. For example, when the motor 120 is deactivated, the engine 110 can 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 can each be operated to propel the vehicle via the drive wheels 130 as indicated by arrows 112 and 122, respectively. The configuration where both the engine and the motor can selectively propel the vehicle can be referred to as a parallel-type vehicle propulsion system. It should be noted that in some embodiments, the motor 120 can propel the vehicle via a first set of drive wheels, while the engine 110 can 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, where the engine does not directly propel the drive wheels. Instead, the engine 110 can be operated to power the motor 120, which in turn can 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, and the generator 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 in turn can provide a generator function to convert the engine output into electrical energy, where the electrical energy can be stored in the energy storage device 150 for subsequent use by the motor.

[0021] The fuel system 140 may include one or more fuel tanks 144 for storing fuel on 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 on the vehicle as a blend of two or more different fuels. For example, the 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 the engine 110, as indicated by arrow 142. Still other suitable fuels or fuel blends may be supplied to the engine 110, where they may be burned at the engine to produce an engine output. The engine output may be utilized to propel the vehicle as indicated by arrow 112 or to recharge the energy storage device 150 via the motor 120 or the generator 160.

[0022] In some embodiments, the energy storage device 150 may be configured to store electrical energy, which may be supplied to other electrical loads (other than the motor) residing on the vehicle, 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 sensed 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. Additionally, 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 sensed feedback. The control system 190 may receive an indication of an operator request for an output of the vehicle propulsion system from the vehicle operator 102. For example, the control system 190 may receive sensed feedback from a pedal position sensor 194 in communication with a pedal 192. The pedal 192 may schematically refer to a friction pedal and / or a drive pedal.

[0024] As indicated by arrow 184, the energy storage device 150 can periodically receive electrical energy from a power source 180 (e.g., not part of the vehicle) residing outside the vehicle. As a non-limiting example, the vehicle propulsion system 100 can be configured as a plug-in hybrid electric vehicle (HEV), such that electrical energy can be supplied from the power source 180 to the energy storage device 150 via an electrical power transmission cable 182. During the operation of recharging the energy storage device 150 from the power source 180, the power transmission cable 182 can electrically couple the energy storage device 150 and the power source 180. When the vehicle propulsion system operates to propel the vehicle, the power transmission cable 182 can be disconnected between the power source 180 and the energy storage device 150. The control system 190 can identify and / or control the amount of electrical energy stored at the energy storage device, which amount of electrical energy can be referred to as the state of charge (SOC).

[0025] In other embodiments, the power transmission cable 182 can be omitted, where electrical energy can be received wirelessly from the power source 180 at the energy storage device 150. For example, the energy storage device 150 can receive electrical energy 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 any suitable method can be used to recharge the energy storage device 150 from a power source (such as from solar or wind energy) that is not part of the vehicle. In this way, the motor 120 can propel the vehicle by utilizing an energy source different from the fuel utilized by the engine 110.

[0026] The fuel system 140 can periodically receive fuel from a fuel source residing outside the vehicle. As a non-limiting example, the vehicle propulsion system 100 can be refueled by receiving fuel via a fuel dispensing device 170, as indicated by arrow 172. In some embodiments, the fuel tank 144 can 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 can 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) can 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 stability control sensors, such as lateral and / or longitudinal and / or yaw rate sensors 199. The vehicle instrument panel 196 may include indicator lights and / or a text-based display in which messages are displayed to the operator. The vehicle instrument panel 196 may also include various input sections for receiving operator input, such as buttons, touchscreens, voice input / recognition, etc. For example, the vehicle instrument panel 196 may include a fueling button 197 that the vehicle operator may manually actuate or press to initiate fueling. For example, as described in more detail below, in response to the vehicle operator actuating the fueling button 197, the fuel tank in the vehicle may be depressurized so that fueling can be performed.

[0028] In an alternative embodiment, the vehicle instrument panel 196 may transmit an audio message to the operator without display. Additionally, the sensor 199 may include a vertical rate of change of speed sensor for indicating road roughness. These devices may be connected to the control system 190.

[0029] Figure 2 A schematic diagram of a vehicle system 206 is shown. The vehicle system 206 includes an 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 may be used to capture and store fuel vapor. In some examples, the vehicle system 206 may be a hybrid electric vehicle system, such as Figure 1 the vehicle propulsion system 100.

[0030] The engine system 208 may include an engine 210 having a plurality of cylinders 230. In one example, the engine 210 is an Figure 1 embodiment of the engine 110. The engine 210 includes an engine intake 223 and an engine exhaust 225. The engine intake 223 includes a throttle 262 that is fluidly coupled to the engine intake manifold 244 via an intake passage 242. The engine exhaust 225 includes an exhaust manifold 248 that leads to an exhaust passage 235 that directs the exhaust to the atmosphere. The engine exhaust 225 may include one or more emissions control devices 270 that may be mounted at a close-coupled location in the exhaust. The one or more emissions 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] The FOH regeneration passage 332 can be arranged downstream of the emission control device 270 and upstream of the exhaust gas regulating valve 234. When FOH regeneration is requested, the FOH regeneration passage 332 can divert exhaust gas from the exhaust passage 235 to the FOH. The exhaust gas regulating valve 234 can be moved to a more closed position to facilitate the inflow of exhaust gas into the FOH regeneration passage 332. Regarding Figure 3 The FOH regeneration passage 332 and the exhaust gas regulating valve 234 are described in more detail.

[0032] The fuel system 218 can include a fuel tank 220 coupled to a fuel pump system 221. In one example, the fuel tank 220 includes Figure 1 the fuel tank 144. The fuel pump system 221 can include one or more pumps for pressurizing fuel delivered to an injector (such as the exemplary injector 266 shown) of the engine 210. Although a single injector 266 is shown, additional injectors are provided for each cylinder. It should be understood that the fuel system 218 can be a returnless fuel system, a return fuel system, or various other types of fuel systems.

[0033] Vapors generated in the fuel system 218 can be directed via a vapor line 231 to an evaporative emissions control system 251 before being drawn into the engine intake 223, and the evaporative emissions control system includes a fuel vapor canister 222. The vapor line 231 can be coupled to the fuel tank 220 via one or more conduits and can include one or more valves for isolating the fuel tank during certain conditions. For example, the vapor recovery line 231 can be coupled to the fuel tank 220 via one or more of the conduits 271, 275, and 276 or a combination thereof.

[0034] Additionally, in some examples, one or more fuel tank vent valves can be located in the conduits 271, 275, or 276. Among other functions, the fuel tank vent valves can also allow the fuel vapor canister of the emissions control system to remain at a low pressure or in a vacuum without increasing the fuel evaporation rate of the fuel tank (which would otherwise occur in the case of a reduced fuel tank pressure). For example, the conduit 271 can include a fuel tank isolation valve (FTIV) 252. The conduit 275 can include a relief valve (RV) 285. In one example, the conduit 275 is a bypass conduit, where the RV 285 is configured to allow vapor flow to the canister 222 when the FTIV 252 is closed. Further, in some examples, the vapor line 231 can be coupled to a fuel fill system 219. In some examples, the fuel fill system 219 can include a fuel tank cap 205 for sealing the fuel filling system from the atmosphere. The fuel fill system 219 is coupled to the fuel tank 220 via a fuel fill tube 211.

[0035] Additionally, the fueling system 219 may include a fueling lock 245. In some embodiments, the fueling lock 245 may be a fuel tank lid locking mechanism. The fuel tank lid locking mechanism may be configured to automatically lock the fuel tank lid 205 in a closed position such that the fuel tank lid cannot be opened. For example, when the pressure or vacuum in the fuel tank 220 is greater than a threshold, the fuel tank lid 205 may be held locked via the fueling lock 245. In response to a fueling request, such as a request initiated by a vehicle operator via actuation of a fueling button on the vehicle dashboard (such as Figure 1 the fueling button 197 on the vehicle dashboard 196), the fuel tank may be depressurized, and the fuel tank lid may be unlocked after the pressure or vacuum in the fuel tank drops below the threshold. In this context, unlocking the fueling lock 245 may include unlocking the fuel tank lid 205.

[0036] In some embodiments, the fueling lock 245 may be a fill tube valve located at the mouth of the fill tube 211. In such embodiments, the fueling lock 245 may not prevent the removal of the fuel tank lid 205. Instead, the fueling lock 245 may prevent a fueling pump from being inserted into the fill tube 211. The fill tube valve may be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure diaphragm.

[0037] In some embodiments, the fueling lock 245 may be a fueling door lock, such as a clutch that locks a fueling door located in a body panel of the vehicle. The fueling door lock may be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure diaphragm.

[0038] In embodiments where an electrical mechanism is used to lock the fueling lock 245, the fueling lock 245 may be unlocked by a command from the controller 212, for example, when the fuel tank pressure drops below a pressure threshold. In embodiments where a mechanical mechanism is used to lock the fueling lock 245, the fueling lock 245 may be unlocked via a pressure gradient, for example, when the fuel tank pressure drops to atmospheric pressure.

[0039] The emission control system 251 may include one or more fuel vapor canisters 222 (also simply referred to herein as canisters) filled with a suitable adsorbent, which are configured to temporarily trap fuel vapors (including vaporized hydrocarbons) generated during fuel tank refueling operations and "running loss" vapors (i.e., fuel vaporized 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 gas from the fuel vapor canister 222 to the atmosphere when storing or trapping 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, gas may be directed to a first canister of more than one canister, then from the first canister to a second canister of more than one canister, and so on for additional canisters of one or more canisters. When the canisters are arranged in parallel, the total volume of gas directed through more than one canister may be directed to a first canister or a second canister, or the total volume of gas may be divided into two volumes, where a first volume of the two volumes is directed through a first canister and a second volume of the two volumes is directed through a second canister.

[0040] When stored fuel vapors are drawn from the fuel system 218 to the engine intake 223 via a draw line 228 and a draw valve 261, the vent line 227 may also allow fresh air to be drawn into the canister 222 via a vent valve 229. For example, the draw valve 261 may be normally closed but may open during certain conditions (such as certain engine operating conditions) such that a vacuum from the engine intake manifold 244 is applied to the fuel vapor canister for drawing. 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 controlled by a canister vent valve 229.

[0041] The evaporative emissions detection procedure can be intermittently performed by the controller 212 on the fuel system 218 to confirm that the fuel system has not deteriorated. Thus, the evaporative emissions detection procedure can be performed using the engine-off natural vacuum (EONV) generated due to the change in temperature and pressure at the fuel tank after engine shutdown and / or vacuum supplemented from a vacuum pump when the engine is off (engine-off leak test). Alternatively, the evaporative emissions detection procedure can be performed while the engine is running by operating a vacuum pump and / or using engine intake manifold vacuum. The evaporative emissions test can be performed by an evaporative leak check module (ELCM) 295 communicatively coupled to the controller 212. The ELCM 295 can be coupled between the canister 222 and the vent valve 229 in the vent line 227. The ELCM 295 can include a vacuum pump configured to apply a negative pressure to the fuel system when in a first configuration (such as when performing a leak test). The ELCM 295 can also include a reference orifice and a pressure sensor 296. After applying a vacuum to the fuel system, the pressure change (e.g., absolute change or rate of change) at the reference orifice can be monitored and compared to a threshold. Based on the comparison, evaporative emissions from the fuel system can be identified. The ELCM vacuum pump can be a reversible vacuum pump and is thus configured to apply a positive pressure to the fuel system when the bridging circuit is reversed to place the pump in a second configuration.

[0042] The canister 222 can include a first buffer zone 224 surrounding the load port 213. Like the canister 222, the buffer zone 224 can also include an adsorbent. The volume of the buffer zone 224 can be less than the volume of the canister 222 (e.g., a portion thereof). The adsorbent in the buffer zone 224 can be the same as or different from the adsorbent in the canister (e.g., both can include charcoal). The buffer zone 224 can be located within the canister 222 such that during canister loading through the load port 213, fuel tank vapor is first adsorbed within the buffer zone and then, when the buffer zone is saturated, additional fuel tank vapor is adsorbed within the body of the canister. In contrast, during canister draw (where air is drawn in through the vent line 227), fuel vapor is first desorbed from the canister (e.g., to a threshold amount) and then from the buffer zone. In contrast, during canister draw (where air is drawn in through the vent line 227), fuel vapor is first desorbed from the canister (e.g., to a threshold amount) and then from the buffer zone. In other words, the loading and unloading of the buffer zone 224 is not coincident with the loading and unloading of the canister. Thus, the effect of the canister buffer is to dampen any fuel vapor spikes flowing from the fuel tank to the canister, thereby reducing the likelihood of any fuel vapor spikes entering the engine or being released through the exhaust tailpipe.

[0043] The fuel tank 220 is fluidly coupled to the canister 222 via an outlet conduit 276 that branches from a fuel tank isolation valve (FTIV) 252 that controls the flow of fuel tank vapor from the fuel tank 220 and through an inlet conduit 271 into the canister 222. By adjusting the 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 that couples 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, adjusting the position of the FTIV 252 to a first position can direct the fuel vapor flow from the fuel tank 220 to a first canister, to a second position can direct the fuel vapor flow from the fuel tank 220 to a second canister, and to a third position can direct the fuel vapor flow from the fuel tank 220 to both the first and second canisters. The FTIV 252 can also be actuated to a fourth closed position.

[0044] For example, when the emissions control system 251 includes one canister 222, the FTIV 252 can be actuated to a closed position that isolates the fuel tank 220 from the canister 222, where no fuel vapor flows through the conduit 276. The controller 212 can command the FTIV position based on fuel system conditions including an operator's request for refueling, fuel tank pressure, and canister loading. In a second example, the position of the FTIV 252 includes a 0.03” orifice to limit the vapor flow to the canister.

[0045] In a configuration where the vehicle system 206 is a hybrid electric vehicle (HEV), the fuel tank 220 can be configured as a sealed fuel tank that can withstand the pressure fluctuations typically encountered during normal vehicle operation and daily temperature cycling (e.g., a steel fuel tank). Additionally, the size of the canister 222 can be reduced to account for reduced engine operation time in a hybrid vehicle. However, for the same reason, an HEV may also have limited opportunities for canister purge operations. Thus, using a sealed fuel tank with a closed FTIV (also known as a NIRCOS or non-integrated refueling canister only system) prevents daytime and running loss vapor from loading the fuel vapor canister 222 and restricts fuel vapor canister loading to only refueling vapor. The FTIV 252 can 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 fill tube 211. Specifically, when the emissions control system 251 includes one canister 222, the FTIV 252 can be actuated to a first open position to depressurize the fuel tank to the canister via a first conduit 276 and a canister load port 213.

[0046] In some embodiments (not shown), a pressure control valve (PCV) (e.g., RV 285) may be configured in a conduit that is parallel to conduit 276 and that couples fuel tank 220 to charcoal canister 222. When included, the RV may be controlled by the powertrain control module (e.g., controller 212) using a pulse width modulation cycle to relieve any excessive pressure generated in the fuel tank, such as during engine operation. Additionally or alternatively, for example, in the case of a hybrid electric vehicle, the RV may be pulse width modulated to vent excessive pressure in the fuel tank when the vehicle is operating in an electric vehicle mode.

[0047] When transitioning to a second (open) position for an emissions control system 251 having one charcoal canister 222, the FTIV 252 allows fuel vapor to be vented from fuel tank 220 to charcoal 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.

[0048] For an emissions control system 251 having at least one charcoal canister 222 (including more than one charcoal canister 222 arranged in parallel), fuel vapor may be stored in the charcoal canister 222, and air stripped from the fuel vapor exits into the atmosphere via the canister vent valve 229. When engine conditions permit, the fuel vapor stored in the charcoal canister 222 may be purged to the engine intake 223 via the purge valve 261. After the fuel tank is sufficiently depressurized (such as below a second threshold pressure), the fuel fill lock 245 may be unlocked to open the fuel tank cap.

[0049] In the absence of an input from controller 212, the RV 285 may open during a condition where the fuel tank pressure exceeds a threshold fuel tank pressure. This may occur during a condition where controller 212 is in a sleep state, which may occur when the engine is off and / or when the vehicle is off. In other examples, a venting event while controller 212 is in a sleep state may not be tracked, resulting in insufficient canister cleaning, which may cause vapor to be released to the atmosphere. This may be exacerbated in a hybrid vehicle where the engine may be off for extended periods of vehicle operation. In one example, the evaporative emissions control system 251 may be fluidly coupled to a fuel-operated heater (FOH) system via a first channel 302 and a second channel 304. Regarding Figure 3 The FOH system is shown in more detail. The FOH system may be operated to direct hot air to the charcoal canister 222, which may release vapor therefrom during a desired condition. The operation of the FOH system is described in more detail below.

[0050] The vehicle system 206 may also include a control system 214 (such as Figure 1control system 190). 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, 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, pressure sensor 291 provides an estimate of the fuel system pressure. In one example, the fuel system pressure is the fuel tank pressure, such as the pressure within fuel tank 220. Other sensors (such as pressure, temperature, air-fuel ratio, and composition sensors) may be coupled at various locations within vehicle system 206. As another example, actuators may include fuel injectors 266, throttle 262, FTIV 252, fuel fill lock 245, canister vent valve 229, and purge valve 261. 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 computer-readable instructions or codes corresponding to one or more programs programmed in the input data. Controller 212 receives signals from Figures 1 to 2 various sensors and employs Figures 1 to 2 various actuators to adjust engine operation based on the received signals and instructions stored in the controller's memory.

[0051] Turning now to Figure 3 , which shows the FOH system 300. The FOH system 300 may 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 may intersect the purge line 228 at the junction between the canister 222 at the first end and the purge valve 261. The first channel 302 may intersect the FOH inlet channel 315 at a location upstream of the FOH 310 with respect to the air flow direction. A first valve 303 may be disposed in the first channel 302 and configured to control the vapor flow from the canister 222 to the FOH inlet channel 315. The first valve 303 may be adjusted to a fully closed position, a fully open position, or any position therebetween based on the purge conditions of the canister 222.

[0052] The FOH inlet passage 315 can be further coupled to the FOH regeneration passage 332 and the fresh air inlet 334. In one example, the FOH inlet passage 315 and the regeneration passage 332 can form a single passage extending from the engine's exhaust system to the FOH 310. The regeneration valve 330, which can be a multi-position valve, can be disposed at the intersection between the FOH regeneration passage 332, the fresh air inlet 334, and the FOH inlet passage 315. The regeneration valve 330 can be configured to allow air to flow only from the fresh air inlet 334 to the FOH inlet passage 315 during a first condition (such as when the FOH is active). The regeneration valve 330 can be configured to allow only exhaust gas to flow from the FOH regeneration passage 332 to the FOH inlet passage 315 during a second condition (such as a regeneration condition). During a condition when the engine is not combusting, engine compression gas can flow through the regeneration passage 332. The regeneration valve 330 can also be configured to allow only a mixture of fresh air from the fresh air inlet 334 and exhaust gas from the FOH regeneration passage 332 to flow to the FOH inlet passage 315 during a third condition, such as when the FOH is preheated for a regeneration event. In this way, the regeneration valve 330 is a three-way valve.

[0053] In some examples, additionally or alternatively, the regeneration valve 330 can be configured as a four-way valve. In such embodiments, the regeneration valve 330 can be disposed at a four-way intersection between the first passage 302, the fresh air inlet 334, the FOH regeneration passage 332, and the FOH inlet passage 315. In this example, the regeneration valve 330 can be configured to control the air flow, exhaust gas flow, and vapor flow to the FOH 310.

[0054] The FOH 310 can be configured to combust the fuel provided by the FOH injector 317. The exhaust passage injector 320 can be positioned to inject directly into the exhaust passage 235 upstream of the emission control device 270.

[0055] When combusting the fuel, the FOH 310 can heat the air provided from the atmosphere through the clean air inlet 306. The heated air can be discharged through the FOH outlet 312. The combustion gas can be discharged from the FOH 310 via the exhaust outlet 314. The exhaust outlet 314 can direct the combustion gas directly to the atmosphere. In one example, additionally or alternatively, the exhaust outlet 314 can direct the combustion gas to Figure 2at a location upstream of the engine exhaust port 225 of the emission control device 270. The combustion gases of the FOH 310 do not mix with the cold air or the heated air flowing through it. In one example, the FOH 310 may include at least one combustion chamber 311 having an ignition device 313 and an FOH injector 317. Fuel and air may be supplied to the combustion chamber, where the air may flow outside and around the at least one combustion chamber. The FOH 310 may receive fuel via a fuel pump (e.g., Figure 2 the fuel pump 221). Additionally or alternatively, fuel vapor from the fuel tank 222 may be the fuel source for the FOH 310. Thus, in one example, the FOH 310 may include a clean air inlet 306, where the air provided from the clean air inlet becomes heated air and does not mix with the fuel vapor or the liquid fuel. In one example, the clean air inlet may be a single continuous passage having an FOH outlet 312. The air may be heated due to combustion, where the heated air is directed to the FOH outlet 312.

[0056] The cabin heating valve 316 may be disposed in the FOH outlet 312 at a location downstream of the 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 therebetween based on a cabin heating request. The position of the cabin heating valve 316 may be further adjusted based on the engine operation in combination with the cabin heating request. In one example, the cabin heating valve may control the airflow from the FOH 310 to the vehicle interior.

[0057] The second valve 305 may be disposed in the second passage 304. The second valve 305 is configured to control the heated airflow 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 location between the fuel tank 222 and the ELCM 295. 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. 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.

[0058] Figure 3The arrows included therein indicate the directions in which gas can flow during various conditions of the FOH system 300 during regeneration of the FOH 310. Regeneration of the FOH 310 can be signaled based on feedback from the differential pressure sensor 318 of the FOH 310. The differential pressure sensor 318 can sense the pressure difference (e.g., differential pressure) between the FOH inlet passage 315 and the exhaust outlet 314. If the pressure difference is positive, the combustion chamber 311 of the FOH 310 may be clogged or fouled with soot particles and cleaning may be requested. A coked combustion chamber 311 may reduce combustion efficiency and / or may inhibit the intake air flow into the combustion chamber 311. In one example, the exhaust control valve 234 can be partially closed and the regeneration valve 330 can be at least partially opened to allow hot exhaust to flow from the exhaust passage 235 to the FOH 310. If the exhaust is not hot (e.g., below a threshold temperature), the exhaust fuel injector 320 can inject fuel at a location upstream of the emission control device 270. The fuel can burn and raise the temperature of the exhaust. The regeneration (e.g., cleaning) of the FOH 310 is described in more detail below.

[0059] Now turning to Figure 4 , which shows a method 400 for cleaning the FOH. Gas from the engine can be used to facilitate regeneration (e.g., cleaning) of the FOH, thereby reducing the load on the combustion chamber of the FOH. Instructions for implementing method 400 and the remaining methods included herein can be executed by a controller based on instructions stored in the controller's memory and in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to Figures 1 to 3 . The controller can employ engine actuators of the engine system to adjust engine operation according to the methods described below.

[0060] Method 400 begins at 402, which includes determining current operating parameters. The current operating parameters can include, but are not limited to, one or more of manifold vacuum, engine speed, engine temperature, vehicle speed, and air / fuel ratio.

[0061] At 404, method 400 can include determining the differential pressure across the FOH. The differential pressure can be sensed via a differential pressure sensor of the FOH. Additionally or alternatively, the differential pressure can be inferred based on the position of the regeneration valve and the flow rate through the FOH outlet passage.

[0062] At 406, method 400 can include determining whether the pressure difference is equal to zero. If the pressure difference is equal to zero, the combustion chamber of the FOH may be fouled within a threshold amount and, at 408, method 400 can include not regenerating the FOH.

[0063] In some examples, additionally or alternatively, it can be used in combination with FOH to track the duration elapsed since the previous regeneration to determine whether regeneration is needed. In this way, regeneration of FOH can occur dynamically. Additionally or alternatively, when conditions are met and EGR is not requested, such as during low load or medium load, coasting events, and other engine shutdown events (e.g., pure electric operation), regeneration of FOH can be performed. As another example, FOH regeneration can be signaled periodically based on the amount of time elapsed, the mileage traveled, and the time of use.

[0064] At 409, method 400 can include maintaining the regeneration valve in a first closed position and maintaining the exhaust gas regulating valve in an open position. The first closed position of the regeneration valve can include: where only fresh air can flow to the FOH and prevent exhaust gas from flowing from the exhaust passage to the FOH.

[0065] If the pressure difference is not equal to zero, then at 410, method 400 can include determining whether the exhaust gas temperature is greater than a threshold temperature. The threshold temperature can be based on a non - zero positive number. The threshold temperature can be equal to the temperature at which soot particles and unburned hydrocarbons can start to burn without a spark. If the exhaust gas temperature is higher than the threshold temperature, then at 412, method 400 can include passively regenerating the FOH.

[0066] At 414, method 400 can include pre - heating the heat exchanger of the FOH. In one example, the heat exchanger is included in the combustion chamber. Pre - heating the heat exchanger can include starting the FOH. Thus, the FOH can be fueled and start to burn until a determined pre - heating temperature is reached, which can include operating the FOH for a threshold duration. The determined pre - heating temperature can be based on a non - zero positive number. The threshold duration can be based on a non - zero positive number. During some cleaning conditions, the FOH may become fouled (e.g., coked) beyond a threshold fouling, such that combustion may not occur within the FOH. In such examples, a metered amount of exhaust gas can be directed towards the FOH. The metered amount of exhaust gas can be mixed with ambient air to control the temperature rise of the FOH, which can be achieved by placing the regeneration valve in a mixed open position. In one example, as the FOH temperature rises towards the determined pre - heating temperature, more exhaust gas can be delivered to the FOH. Thus, the regeneration valve can be adjusted to a position that opens more towards the FOH regeneration passage and less towards the fresh air inlet.

[0067] At 416, method 400 may include actuating a regeneration valve to an open position. In one example, the open position is a second open position of the regeneration valve. The second open position may only allow exhaust gas from the exhaust passage to flow to the FOH. The regeneration valve may also include a first open position, a mixed open position, and a fully closed position. The first open position may only allow fresh air to flow to the FOH. The mixed open position may be a combination of the first open position and the second open position, where both fresh air and exhaust gas may flow to the FOH. The closed position of the FOH regeneration valve may include: where the fresh air and exhaust gas flow to the FOH are blocked.

[0068] At 418, method 400 may include actuating an exhaust gas regulating valve to a partially closed position. In this way, the exhaust gas can be directed through the regeneration passage and through the vehicle's exhaust tailpipe.

[0069] At 420, method 400 may include flowing exhaust gas to the FOH. The exhaust gas may ignite soot particles and initiate cleaning of the FOH. Thus, during passive regeneration of the FOH, no fuel may be supplied to the FOH or the exhaust gas. The exhaust gas temperature is higher than a threshold temperature, and the soot particles coked onto the FOH can be ignited without fuel or other combustibles.

[0070] At 422, method 400 may include monitoring the differential pressure across the FOH.

[0071] At 424, method 400 may include determining whether the differential pressure is equal to zero. If the differential pressure is not equal to zero or another determined differential pressure, indicating that the FOH is cleaned, method 400 may continue to flow exhaust gas to the FOH.

[0072] If the differential pressure is equal to zero or another determined differential pressure, indicating that the FOH is cleaned, then at 426, method 400 may include deactivating FOH regeneration. Deactivating FOH regeneration may include actuating the regeneration valve to the fully closed position or the first open position and fully opening the exhaust gas regulating valve.

[0073] Returning to 410, if the exhaust gas temperature is not higher than the threshold temperature, then at 428, method 400 may include determining whether the engine is burning. If the engine is being fueled at that time, the engine is burning. If the engine is burning and producing exhaust gas, then at 430, method 400 may include actively regenerating the FOH.

[0074] At 432, method 400 may include injecting fuel into the exhaust stream upstream of the aftertreatment device. In one example, an exhaust passage injector may be activated and begin injecting fuel into the exhaust passage, where the fuel may combust and raise the exhaust temperature toward a threshold temperature. The aftertreatment device may process the exhaust. Additionally or alternatively, active regeneration may include injecting fuel into the FOH. The fuel injected into the FOH may ignite in the presence of exhaust, which may initiate regeneration of the FOH. Active regeneration may continue to perform 416 - 424 of the passive regeneration procedure.

[0075] In some examples, active regeneration may be initiated only during conditions where the use of the FOH is requested and cleaning is needed. If cleaning is needed and the use of the FOH is not requested, the method may include waiting until passive regeneration conditions are met. By doing so, the efficiency of regeneration can be increased.

[0076] Returning to 428, if the engine is not combusting, method 400 proceeds to Figure 5 502 of method 500, which includes determining whether the vehicle is on. If the ignition key is turned or the ignition button is pressed, the vehicle may be on. Additionally or alternatively, in response to the pedal being depressed, the vehicle may be on. If the vehicle is not on, at 504, method 500 may include not regenerating the FOH. Thus, the FOH may not be heated, and the soot particles coked on the FOH may not combust.

[0077] If the vehicle is on, at 506, method 500 may include cranking the engine. The vehicle may be on and not combusting, such as during a coasting event or pure electric operation of the vehicle. Thus, method 500 may appropriately regenerate the FOH during non - combusting operations when the vehicle is on.

[0078] At 508, method 500 may include actuating the regeneration valve to a second open position. Thus, the intake air of the cranking engine may flow to the FOH. That is, the engine may crank and compress ambient air such that the pressure of the ambient air increases as it flows into the exhaust passage.

[0079] At 510, method 500 may include actuating the exhaust control valve to a partially closed position.

[0080] At 512, method 500 may include flowing compressed air from the engine to the FOH.

[0081] At 514, method 500 may include fueling the FOH. Thus, the FOH injector may be activated and begin injecting fuel into the combustion chamber (e.g., heat exchanger) of the FOH. The fuel may mix with the engine compressed air and be ignited by compression or spark. The combustion of the fuel and air may initiate regeneration of the FOH.

[0082] At 516, method 500 may include monitoring the differential pressure across the FOH.

[0083] At 518, method 500 may include determining whether the differential pressure is equal to zero. If the differential pressure is not equal to zero, method 500 continues to have the engine compress air flow to the FOH while injecting fuel into the FOH. Thus, if the differential pressure is not equal to zero, regeneration can continue. If the differential pressure is equal to zero, regeneration can be stopped. Stopping regeneration may include closing the regeneration valve, opening the exhaust regulating valve, and no longer rotating the engine to start.

[0084] Now turning to Figure 6 , which shows a graph 600 depicting an operating sequence graphically displaying the regeneration status of the FOH. Curve 610 shows the engine exhaust temperature, dashed line 612 shows the threshold temperature, and dashed curve 614 shows the elevated exhaust temperature. Curve 620 shows the regeneration valve position. Curve 630 shows the position of the exhaust regulating valve. Curve 640 shows the FOH differential pressure. Curve 650 shows the exhaust fuel injector status. Time increases from the left side to the right side of the drawing.

[0085] Before t1, the FOH differential pressure is relatively high. Thus, the differential pressure is not equal to zero, and regeneration of the FOH is requested. The engine exhaust temperature is below the threshold temperature. At t1, the exhaust fuel injector is activated. Thus, fuel is injected into the exhaust stream. Thus, an elevated exhaust temperature can be achieved relative to the engine exhaust temperature between t1 and t2.

[0086] At t2, the elevated exhaust temperature is equal to the threshold temperature. Thus, the regeneration valve moves to the open position allowing exhaust flow to the FOH. The exhaust regulating valve moves to a partially closed position between the fully open position and the fully closed position.

[0087] Between t2 and t3, the FOH differential pressure begins to decrease, indicating that the FOH is actively regenerating to a less coked state.

[0088] At t3, the engine exhaust temperature begins to rise, which may be due to an increase in engine load. In one example, as the engine exhaust temperature rises towards the threshold temperature between t3 and t4, the amount of fuel injected by the exhaust fuel injector can be reduced. By doing so, the elevated exhaust temperature can be controlled to mitigate overheating of the FOH.

[0089] At t4, the engine exhaust temperature is equal to the threshold temperature. Thus, the exhaust fuel injector is deactivated. Between t4 and t5, the FOH is regenerated only via the engine exhaust. Thus, passive regeneration of the FOH occurs, and fuel is not injected into the FOH or the exhaust passage.

[0090] At t5, the FOH incremental pressure is equal to zero. Accordingly, regeneration of the FOH can be terminated. Terminating the regeneration can include closing a regeneration valve to block exhaust flow to the FOH and actuating an exhaust regulating valve to a fully open position. After t5, the engine exhaust temperature remains above a threshold temperature. Engine exhaust flow to the FOH is blocked by positioning the regeneration valve in a fully closed position or another position that seals the regeneration passage from the FOH.

[0091] The present disclosure provides support for a system that includes a fuel-operated heater (FOH) fluidly coupled to an exhaust system of an engine. A first example of the system further includes: wherein a regeneration passage extends from the FOH and intersects an exhaust passage of the exhaust system at a location downstream of a post-treatment device relative to the direction of exhaust flow. A second example of the system (which optionally includes the first example) further includes: wherein a valve is disposed in the regeneration passage, the valve being configured to control exhaust flow from the exhaust passage to the FOH. A third example of the system (which optionally includes one or more of the previous examples) further includes: wherein the exhaust system includes an exhaust regulating valve. A fourth example of the system (which optionally includes one or more of the previous examples) further includes a controller having computer-readable instructions that, when executed, cause the controller to initiate regeneration of the FOH in response to an incremental pressure of the FOH. A fifth example of the system (which optionally includes one or more of the previous examples) further includes: wherein the instructions further cause the controller to allow exhaust to flow out of the exhaust system during regeneration of the FOH. A sixth example of the system (which optionally includes one or more of the previous examples) further includes: wherein the exhaust system further includes a fuel injector positioned to inject fuel directly into the exhaust flow.

[0092] The present disclosure provides additional support for a system including a fuel-operated heater (FOH) fluidly coupled to an exhaust system of an engine and to the vehicle interior, and a controller including computer-readable instructions that, when executed, enable the controller to direct exhaust from the exhaust system to the FOH in response to a regeneration request. A first example of the system further includes a fuel injector positioned upstream of a post-treatment device of the exhaust system, the fuel injector positioned to inject fuel directly into the exhaust stream, and wherein the FOH is fluidly coupled to a location downstream of the post-treatment device relative to the direction of the exhaust stream. A second example of the system (which optionally includes the first example) further includes: wherein the instructions further enable the controller to activate the FOH for a threshold duration before directing the exhaust stream to the FOH. A third example of the system (which optionally includes one or more of the previous examples) further includes: wherein the instructions further enable the controller to direct a mixture of exhaust and fresh air to the FOH before directing the exhaust through a multi-position valve to the FOH. A fourth example of the system (which optionally includes one or more of the previous examples) further includes a differential pressure sensor coupled to an inlet and an outlet of the FOH. A fifth example of the system (which optionally includes one or more of the previous examples) further includes: wherein the regeneration request is in response to a differential pressure sensed by the differential pressure sensor. A sixth example of the system (which optionally includes one or more of the previous examples) further includes: wherein the FOH is deactivated and not fueled when the exhaust is directed to the FOH. A seventh example of the system (which optionally includes one or more of the previous examples) further includes: wherein the instructions further enable the controller to crank the engine and direct engine compressed air to the FOH in response to the presence of a regeneration request when the engine is not fueled.

[0093] The present disclosure provides further support for a method including: activating a fuel-operated heater (FOH) for a threshold duration; deactivating the FOH; and directing exhaust from the engine to the FOH. A first example of the method optionally includes injecting fuel into the exhaust stream in response to the temperature of the exhaust being below a threshold temperature. A second example of the method (which optionally includes the first example) optionally includes maintaining FOH activity and cranking the engine in response to the engine not being fueled. A third example of the method (which optionally includes one or more of the previous examples) further includes: wherein a metered amount of exhaust is delivered to the FOH in response to the FOH not being activated for a threshold duration. A fourth example of the method (which optionally includes one or more of the previous examples) further includes: wherein a metered amount of exhaust is mixed with fresh air before contacting the FOH.

[0094] Note that the example control and estimation routines included herein can be used with a variety of engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Accordingly, the various acts, operations, and / or functions shown can be executed in the sequence shown, executed in parallel, or in some cases omitted. Likewise, the order of processing 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 acts, operations, and / or functions shown can be repeatedly executed in accordance with the particular strategy used. Further, the acts, operations, and / or functions described can be graphically represented as code to be programmed into the non-transitory memory of a computer-readable storage medium for an engine control system, where the acts are implemented by executing the instructions in a system including various engine hardware components in conjunction with an electronic controller.

[0095] It should be understood that the configurations and routines disclosed herein are exemplary in nature and these specific embodiments should not be considered to be limiting in a limiting sense, as many variations are possible. For example, the above techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0096] As used herein, unless otherwise specified, the term "about" is interpreted to mean ±5% of a range.

[0097] The appended claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims are to be understood to include the combination of one or more such elements, neither requiring nor precluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the claims or by filing new claims in this or a related application. Such claims, whether broader, narrower, equivalent, or different in scope from the original claims, are also regarded as included within the subject matter of the present disclosure.

[0098] According to the present invention, there is provided a system having: a fuel-operated heater (FOH) fluidly coupled to an exhaust system of an engine.

[0099] According to an embodiment, a regeneration passage extends from the FOH and intersects an exhaust passage of the exhaust system at a location downstream of the aftertreatment device in the direction relative to the exhaust flow.

[0100] According to an embodiment, a valve is disposed in the regeneration passage, and the valve is configured to control the exhaust from the exhaust passage to the FOH.

[0101] According to an embodiment, the exhaust system includes an exhaust regulating valve.

[0102] According to an embodiment, the present invention further features a controller having computer-readable instructions that, when executed, cause the controller to initiate regeneration of the FOH in response to an incremental pressure of the FOH.

[0103] According to an embodiment, the instructions further cause the controller to allow the exhaust to flow out of the exhaust system during regeneration of the FOH.

[0104] According to an embodiment, the exhaust system further includes a fuel injector positioned to directly inject fuel into the exhaust stream.

[0105] According to the present invention, there is provided a system having: a fuel-operated heater (FOH) fluidly coupled to an exhaust system of an engine and the interior of a vehicle; and a controller including computer-readable instructions that, when executed, enable the controller to direct exhaust from the exhaust system to the FOH in response to a regeneration request.

[0106] According to an embodiment, the present invention further features a fuel injector positioned upstream of an aftertreatment device of the exhaust system, the fuel injector being positioned to directly inject fuel into the exhaust stream, and wherein the FOH is fluidly coupled to a location downstream of the aftertreatment device in the direction relative to the exhaust flow of the exhaust system.

[0107] According to an embodiment, the instructions further enable the controller to activate the FOH before directing the exhaust flow to the FOH for a threshold duration.

[0108] According to an embodiment, the instructions further enable the controller to allow a mixture of exhaust and fresh air to flow to the FOH before directing the exhaust to the FOH via a multi-position valve.

[0109] According to an embodiment, the present invention further features a differential pressure sensor coupled to an inlet and an outlet of the FOH.

[0110] According to an embodiment, the regeneration request is in response to a differential pressure sensed by the differential pressure sensor.

[0111] According to an embodiment, when the exhaust is directed to the FOH, the FOH is deactivated and not fueled.

[0112] According to an embodiment, the instructions also enable the controller to crank the engine and cause compressed air from the engine to flow to the FOH in response to a regeneration request when the engine is not combusting.

[0113] According to the present invention, a method includes: activating a fuel-operated heater (FOH) for a threshold duration; deactivating the FOH; and causing exhaust gas to flow from the engine to the FOH.

[0114] In one aspect of the present invention, the method includes injecting fuel into the exhaust gas stream in response to the temperature of the exhaust gas being lower than a threshold temperature.

[0115] In one aspect of the present invention, the method includes maintaining FOH activity and cranking the engine in response to the engine not being fueled.

[0116] In one aspect of the present invention, a metered amount of exhaust gas is delivered to the FOH in response to the FOH not being activated for a threshold duration.

[0117] In one aspect of the present invention, a metered amount of exhaust gas is mixed with fresh air before contacting the FOH.

Claims

1. A system, comprising: A fuel-operated heater (FOH), the FOH being fluidly coupled to an exhaust system of an engine.

2. The system of claim 1, wherein a regeneration passage extends from the FOH and intersects an exhaust passage of the exhaust system at a location downstream of a post-treatment device relative to the direction of the exhaust flow.

3. The system of claim 2, wherein a valve is disposed in the regeneration passage, the valve being configured to control the exhaust flow from the exhaust passage to the FOH.

4. The system of claim 1, wherein the exhaust system includes an exhaust control valve.

5. The system of claim 1, further comprising a controller having computer-readable instructions that, when executed, cause the controller to initiate regeneration of the FOH in response to an incremental pressure of the FOH.

6. The system of claim 5, wherein the instructions further cause the controller to allow exhaust to flow out of the exhaust system during the regeneration of the FOH.

7. The system of claim 1, wherein the exhaust system further includes a fuel injector positioned to directly inject fuel into the exhaust flow.

8. A system, comprising: A fuel-operated heater (FOH), the FOH being fluidly coupled to an exhaust system of an engine and to the interior of a vehicle; And A controller, the controller including computer-readable instructions that, when executed, enable the controller to: Direct exhaust from the exhaust system to the FOH in response to a regeneration request.

9. The system of claim 8, further comprising a fuel injector positioned upstream of a post-treatment device of the exhaust system, the fuel injector being positioned to directly inject fuel into the exhaust flow, and wherein the FOH is fluidly coupled to a location downstream of the post-treatment device of the exhaust system relative to the direction of the exhaust flow.

10. The system of claim 8, wherein the instructions further enable the controller to activate the FOH before allowing the exhaust flow to the FOH for a threshold duration.

11. The system of claim 8, wherein the instructions further enable the controller to allow a mixture of exhaust and fresh air to flow to the FOH before allowing the exhaust to flow to the FOH via a multi-position valve.

12. The system of claim 8, further comprising a differential pressure sensor coupled to an inlet and an outlet of the FOH.

13. The system of claim 12, wherein the regeneration request is in response to a differential pressure sensed by the differential pressure sensor.

14. The system of claim 8, wherein when the exhaust is directed to the FOH, the FOH is deactivated and not fueled.

15. The system of claim 8, wherein the instructions further enable the controller to crank the engine and allow engine compressed air to flow to the FOH in response to the presence of the regeneration request when the engine is not combusting.

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