Vehicle system and method for operating an in-vehicle evaporative emission system with a container

Abstract

Vehicle system, featuring: an internal combustion engine (10); Evaporative emission system (30) with a container (40) arranged to collect fuel vapors from a fuel tank and connected to an intake part of the internal combustion engine (10) via a vent valve (37); wherein the container (40) defines a chamber (41) and a flexible metal-organic framework material (MOF) is arranged in the chamber (41); a controllable device (54) connected to the flexible MOF material; and a control unit (80) which is operationally connected to the controllable device (54) and the vent valve (37), wherein the control unit (80) contains a set of commands which can be executed to: Activating the controllable device (54) and controlling the vent valve (37) in response to a command to vent the container (40) into an open state, Determining an activation parameter for the controllable device (54), Determining a venting flow and a total venting mass, and Deactivating the controllable device (54) if the total venting mass is greater than a threshold value.

Description

[0001] A vehicle with an internal combustion engine can emit volatile hydrocarbons from sources that may include an engine air intake system, a fuel supply system, a fuel tank, and an exhaust gas recirculation (EGR) system. These emissions from the fuel tank and fuel supply system can be captured by means of an evaporative emission control system, which includes an evaporative emission canister (“canister”) filled with activated carbon.

[0002] Activated carbon can be used in a container to adsorb fuel vapor escaping from the fuel system, thus limiting evaporative emissions. The adsorbed fuel vapor is periodically removed from the activated carbon by venting the container with fresh ambient air. This process desorbs the fuel vapor from the activated carbon, regenerating it for further adsorption of fuel vapor.

[0003] Stricter regulations on evaporative emissions are driving the development of improved evaporative emission control systems, particularly for use in vehicles with lower vent volumes, such as hybrid vehicles. These vehicles can otherwise generate high evaporative emissions because the venting frequency is lower, resulting in a smaller overall vent volume and higher residual hydrocarbon shedding. Therefore, it is desirable to have an evaporative emission control system capable of effectively capturing evaporative emissions in vehicles with low vent volumes and / or infrequent venting cycles.

[0004] WO 2018 / 236 935 A1 describes an evaporation emission control container system.

[0005] US Patent 7,553,352 B2 describes a method for absorbing, storing, or absorbing and storing at least one gas, wherein the at least one gas is brought into contact with an electrochemically produced metal-organic framework compound.

[0006] The task can be considered to be to specify an improved method and system for controlling and monitoring an evaporative emission system that captures volatile hydrocarbons that may be emitted from a fuel tank in a vehicle.

[0007] The concepts described here provide a system and a method for controlling and monitoring an in-vehicle system for controlling evaporative emissions, which uses a container with a flexible metal-organic framework material (MOF) in the chamber.

[0008] The vehicle system according to the invention comprises an internal combustion engine and an evaporative emission system with a container. The container is arranged to collect fuel vapors from a fuel tank and is connected to an intake section of the internal combustion engine via a vent valve. The container defines a chamber in which a flexible metal-organic framework material (MOF) is arranged. A controllable device is coupled to the flexible MOF material, and a control unit is operationally connected to the controllable device and the vent valve.The controller contains a set of commands that can be executed to activate the controllable device and control the vent valve to an open state in response to a command to vent the container, to determine an activation parameter for the controllable device, to determine a vent flow, to integrate the vent flow to determine a total vent mass, and to deactivate the controllable device when the total vent mass is greater than a threshold.

[0009] One embodiment involves deactivating the controllable device if the activation parameter for the controllable device is greater than a second threshold.

[0010] One embodiment includes the controllable device being a first heating element located near the flexible MOF material, wherein the activation of the controllable device includes controlling the controllable device in a heat-generating state.

[0011] Another embodiment includes the flexible metal-organic framework material (MOF) arranged in the chamber of the container being a hybrid organic-inorganic material composed by linking metal oxide clusters through rigid organic ligands, wherein the flexible MOF material is reversibly controllable into a first, collapsed state and a second, expanded state in response to a control stimulus, and wherein the control stimulus corresponds to the activation parameter for the controllable device.

[0012] Another aspect of the revelation includes that the first heating element is a PTC (positive temperature coefficient) heating element, a thin-film heating element, or a rod heating element.

[0013] Another embodiment includes a second heating element which is arranged in a flow stream near the vent opening and is activated in response to the command to vent the container.

[0014] Another embodiment involves the controller being operable in such a way that it integrates the activation parameter to determine an integrated activation energy parameter for the controllable device in order to detect a fault associated with the controllable device when the integrated activation energy parameter for the controllable device is either greater than an upper threshold or less than a lower threshold.

[0015] Another embodiment comprises a sensor element arranged to monitor an element of the evaporative emission system and to communicate with the control system. The sensor element is monitored to detect a fault related to the evaporative emission system.

[0016] Another embodiment involves the sensor element being arranged to monitor an electrical circuit of the evaporative emission system in order to detect either an open circuit or a short circuit in the electrical circuit of the evaporative emission system.

[0017] Another embodiment includes the sensor element arranged to monitor a position associated with the flexible metal-organic framework material (MOF) in the container in order to detect a defect in the flexible MOF material based on the position.

[0018] Another embodiment involves the sensor element being arranged to monitor a temperature associated with the flexible MOF material in the container in order to detect a fault in the flexible MOF material based on the temperature.

[0019] Another embodiment involves the sensor element being arranged to monitor a pressure associated with the flexible MOF material in the container in order to detect a defect in the flexible MOF material based on the pressure.

[0020] Another embodiment involves the sensor element being arranged to monitor a venting time associated with the evaporative emission system in order to detect a defect in the flexible MOF material based on the venting time.

[0021] According to the invention, a method for operating an evaporative emission system with a container is described, wherein the container is arranged in such a way that it collects fuel vapors from a fuel tank and is in fluid communication with an intake part of the internal combustion engine via a vent valve, wherein the container defines a chamber with a flexible metal-organic framework material (MOF) that is arranged in the chamber.The method includes controlling the vent valve to an open state in response to a command to vent the container, activating a controllable device coupled to the flexible MOF material, determining an activation parameter for the controllable device, determining a venting flow, integrating the venting flow to determine a total venting mass, and deactivating the controllable device when the total venting mass is greater than a threshold value.

[0022] One or more embodiments are now described by way of example with reference to the attached drawings, in which: Fig. Figure 1 schematically shows parts of an internal combustion engine and an evaporative emission system with an evaporation tank containing a metal-organic framework material (MOF). Fig. Figure 2 schematically shows an embodiment of an evaporation container with several chambers arranged in a series. Fig. Figure 3 shows an example of a flexible MOF material. Fig. Figure 4 shows a part of an exemplary flexible MOF material in a first, collapsed state and in a second, expanded state, as well as an associated control stimulus. Fig. Figure 5 schematically shows a flowchart of a control algorithm for an evaporative emission system for controlling the combustion engine and the evaporative emission system, which refers to Fig. 1 is described. Fig. Figure 6 schematically shows a flowchart of a monitoring algorithm for an evaporative emission system for monitoring the combustion engine and the evaporative emission system, which refers to Fig. 1 is described.

[0023] The term “system” as used here may refer to one or a combination of mechanical and electrical actuators, sensors, controllers, application-specific integrated circuits (ASICs), combinational logic circuits, software, firmware and / or other components arranged to provide the described functionality.

[0024] The term "upstream" and related terms refer here to elements located in the direction of the source of a river relative to a given location, and the term "downstream" and related terms refer to elements moving away from the source of a river relative to a given location. Referring to the drawings, where identical reference numerals correspond to identical or similar components in the various figures, it shows Fig. 1 In accordance with the embodiments disclosed herein, a schematic representation of a part of a multi-cylinder internal combustion engine 10, a fuel storage system 70, and an evaporative emission system 30 for a vehicle. The vehicle may comprise, but is not limited to, a mobile platform in the form of a commercial vehicle, an industrial vehicle, an agricultural vehicle, a passenger car, an aircraft, a watercraft, a train, an all-terrain vehicle, a people carrier, a robot, and the like, in order to fulfill the purposes of this disclosure.

[0025] The depicted part of the internal combustion engine 10 comprises a single combustion chamber 12, which is fluidically connected to an air intake system 20, an intake manifold 14 and an exhaust manifold 18. The components of the internal combustion engine 10 include a fuel injector 13, a throttle valve 15, an airflow sensor 16, and an exhaust gas sensor 19. The air intake system 20 comprises a fresh air inlet 21, which is connected to the intake manifold 14 via a fresh air duct 22, an air filter housing 23, and an intake manifold duct 27. The air filter housing 23 comprises an inlet housing 24, an air filter element 25, and a filtered air housing 26. The fresh air inlet 21, the fresh air duct 22, and the inlet housing 24 of the air filter housing 23 form a fresh air side 28. The filtered air housing 26 of the air filter housing 23, the intake manifold duct 27, and the intake manifold 14 form a filtered air side 29.A vapor barrier element 90 can be arranged in the filtered air housing 26 of the air filter housing 23 on the filtered air side 29 between the air filter element 25 and the intake manifold 14.

[0026] The combustion engine 10 shown is configured as a gasoline engine with port fuel injection. The concepts described here are not limited to such a configuration and can instead be applied to other forms of fuel injection, such as a direct injection system, but are not limited to them. Furthermore, the concepts described here can also be applied to a compression-ignition engine.

[0027] The fuel storage system 70 comprises a fuel storage tank 71, which is connected to an evaporative storage container (“canister”) 40 of the evaporative emission system 30. The fuel storage system 70 supplies fuel via a fuel pump to an engine fuel distribution system, which is connected to the engine's fuel injectors, including the fuel injector 13 shown. The fuel storage tank 71 is fluidically connected to a first opening 31 of the container 40 via a vapor line 35. The container 40 also includes a third port 33, which is connected to the air intake system 20 via a vent line 36 and a vent valve 37. The vent line 36 is connected to the air intake system 20 on the filtered air 29 side, downstream of the throttle valve 15, at or near the intake manifold 14.

[0028] A control unit 80 is arranged to control the operation of the combustion engine 10, including the control elements of the evaporative emission system 30. The control unit 80 communicates with or is operationally linked to various elements via a communication link 38. The communication link 38 enables the transmission of data signals, which may include discrete analog and / or digitized analog signals representing sensor inputs, actuator commands, and communication between control units. This includes the control unit 80 communicating with and / or being operationally linked to the container 40, whereby the control unit 80 receives the control pulse 55 (shown with reference to Fig. 1) or the control pulses 55, 56, 57 (shown with reference to Fig. 2) transmitted to a container, e.g. container 40. The control unit 80 comprises an algorithm for controlling the evaporative emission system (“control algorithm”) 500, which, with reference to Fig. 5 is described, and an algorithm for monitoring the evaporative emission system (“monitoring algorithm”) 600, which refers to Fig. 6 is described.

[0029] The container 40 is arranged as a rigid container that forms and defines a first volumetric chamber 41, which in one embodiment contains a first adsorption material 51. The rigid container can be housed in a fender well of the vehicle, under the hood, or at another location on the vehicle and is dimensioned according to the available space. The rigid container can be configured as a tubular device, a rectangular prismatic device, or another type of device. The container 40 may include internal baffles and other structural elements for arranging the first adsorption material 51 to prevent deposits, etc. The container 40 comprises the first opening 31, a second opening 32, and the third opening 33, as well as associated flow control valves for controlling the vapor flow under different operating conditions. The second opening 32 is a vent opening that releases to the atmosphere.With the engine off, air and vapor from the headspace 72 of the fuel storage tank 71 can flow through the first opening 31 and follow the flow path 34A through the first adsorbent 51 to the second opening 32, due to the vapor pressure generated by the heating of the fuel in the fuel storage tank 71. Advantageously, the vapor is adsorbed by the first adsorbent 51, and only air is released to the atmosphere. During operation of the engine 10, the vent valve 37 can be opened under predefined operating conditions, and air can flow through the second port 32 due to the negative pressure generated by the engine 10, following the flow path 43B through the reservoir 40. The airflow desorbs the adsorbed fuel vapors from the first adsorbent 51 and thus serves to vent the reservoir 40.

[0030] In one embodiment, the first adsorbent 51 is formed from a metal-organic framework (MOF) capable of adsorbing and desorbing hydrocarbon material. In another embodiment, the first adsorbent material 51 is formed by arranging the MOF material with a binder material. In yet another embodiment, the first adsorbing material 51 is formed by applying the MOF material to a substrate. In yet another embodiment, the first adsorbent 51 is the MOF material arranged as a composite material, in the form of beads, spheres, extruded or in another shape, which is cast into and sealed within the chamber 41. The MOF material is configured to adsorb fuel components such as n-butane, isobutane, n-pentane, and 2-methylbutane, and also oxygen-containing components. In yet another embodiment, the first adsorbent material 51 is an MOF material with a pore size between 2 and 2.5 nm.In one embodiment, the first adsorption material is a MOF material with a pore size of less than 5 nm. Further details regarding MOF materials, pore sizes, etc., are given with reference to [reference to be added]. Fig. 6 described. In one embodiment, the first adsorption material 51 comprises a MOF material consisting of metal coordination polymers with copper (Cu) as connecting elements and benzene-1,3,5-tricarboxylate (BTC) ligand as linker, e.g. CuBTC.

[0031] In one embodiment, the first adsorption material 51 is produced as a flexible metal-organic framework (MOF) capable of adsorbing and desorbing hydrocarbon material in response to a control pulse 55. In one embodiment, the flexible MOF material is arranged with a binder material. In one embodiment, the flexible MOF material is applied to a substrate. In one embodiment, the flexible MOF material is arranged as a composite material in the form of beads, spheres, extruded or otherwise shaped pellets, which is cast into and sealed within the chamber 41. In one embodiment, the flexible MOF material has a pore width between 2 and 2.5 nm. In one embodiment, the flexible MOF material has a pore width of less than 5 nm. Further details regarding flexible MOF materials, pore widths, etc., are given with reference to the Fig. 3 and Fig. 4 described.

[0032] Flexible MOF materials are a class of MOF materials that exhibit a dynamic change in pore dimensions in response to an external stimulus. This change in pore dimensions is reversibly controllable into a first or second state, which can be provided by a control stimulus, such as the control stimulus 55. Flexible MOF materials possess the properties of framework flexibility and dynamic response, which distinguish them from other porous materials such as zeolites and activated carbons. Depending on the design and characteristics, flexible MOF materials can exhibit various types and magnitudes of structural dynamics. These include state changes involving expansion and contraction of the pore diameter, also known as the respiration mechanism. The respiration mechanism can be triggered by external chemical stimuli, such as...through the adsorption, desorption, and exchange of guests. The breathing mechanism can instead be triggered by external physical stimuli, such as changes in temperature, light, and / or pressure. Flexible MOF materials are configured to transform into densely packed, small pores capable of adsorbing hydrocarbon vapor when the control stimulus 55 is in the first state. Volatile hydrocarbon vapors can be deposited on the flexible MOF material of the first adsorption material 51 during a motor-off state and / or adsorbed by it when it is driven into the first state by the control pulse 55. The flexible MOF material is configured to transform into loosely packed, large pores capable of desorbing hydrocarbon vapor when the control pulse 55 is in the second state.The hydrocarbon vapor adsorbed by the flexible MOF material 51 during a switched-off state of the motor can be desorbed by the flexible MOF material during a switched-on state if the flexible MOF material is controlled into the second state by the control pulse 55, e.g. during an evaporative venting process.

[0033] The breathing mechanism exhibited by the flexible MOF material in response to the control pulse 55 can facilitate the desorption of hydrocarbon vapors during venting, thus enabling faster and more complete venting of the container 40 compared to a container using only activated carbon. Furthermore, flexible MOFs can store larger quantities of hydrocarbon vapors than similarly sized (by volume) devices using activated carbon.

[0034] As in Fig. As shown in Figure 1, the controller 80 is connected to the container 40 in operational readiness via the control pulse 55. The controller 80 generates the control pulse 55, which is transmitted to the container 40. The control pulse 55 comprises a first state and a second state. The control pulse 55 can be a constant signal, a pulse-width modulated signal, or another modulated signal in the form of an electrical voltage, an electric current, an electromagnetic pulse, emitted light, pressure, etc., without limitation. In one embodiment, a controllable device 54 is integrated into or arranged near the container 40 and is controlled to either the first state or the second state in response to the control pulse 55. In one embodiment, the controllable device 54 is a substrate with electrical resistance, e.g.,The controllable device 54 consists of carbon on which the flexible MOF material 51 is deposited and can be switched to either an on or off state in response to the control pulse 55 to control the container 40. In one embodiment, the controllable device 54 is an electrically operated heating element located near the flexible MOF material 51 and can be switched to either an on or off state in response to the control pulse 55 to control the container 40. In another embodiment, the controllable device 54 comprises a first electrically operated heating element located near the flexible MOF material 51 and a second electrically operated heating element located in the second opening 32, i.e., the vent opening, to heat incoming air during a venting process.The electrically operated heating element(s) can be a PTC (positive temperature coefficient) heating element, a thin-film heating element, or a rod heating element.

[0035] A MOF sensor 59 monitors the flexible MOF material 51 and communicates with the controller 80. In one embodiment, the MOF sensor 59 is integrated into the container 40. In another embodiment, the MOF sensor 59 is an electrical sensor in the controller 80 that monitors the electrical resistance or conductivity across all or part of the flexible MOF material 51. In another embodiment, the MOF sensor 59 is a differential pressure sensor that monitors a differential pressure across all or part of the flexible MOF material 51. In another embodiment, the MOF sensor 59 is a temperature sensor that monitors a temperature of the flexible MOF material 51. In yet another embodiment, the MOF sensor 59 comprises multiple temperature sensors that monitor a temperature difference across all or part of the flexible MOF material 51.

[0036] The flexible MOF material can be one or a combination of MIL-53 Al, the MIL-88 series, ZIF-8, and / or Co(bdp). MIL-53 Al is an aluminum terephthalate MOF; the MIL-88 series is an iron(III) dicarboxylate MOF; ZIF-8 is a zeolitic imidazolate framework consisting of zinc ions coordinated by four imidazolate rings; and Co(bdp) is a cobalt-based MOF with bdp. 2- = 1,4-benzenedipyrazolate linker.

[0037] Alternatively, the adsorbent 40 stored in chamber 41 of container 40 can also be composed of two, three, or more adsorbents mixed together. The adsorbents can be composed of one or more MOF materials with a pore size between 2.5 nm and 5 nm, or a MOF material with a pore size of less than 5 nm, a MOF material with a pore size between 10 nm and 40 nm, a flexible MOF material, an activated carbon material, etc. Various combinations of adsorbent materials can be selected and used to fulfill the task of capturing, storing, and releasing fuel vapor components.

[0038] Fig. Figure 2 schematically shows an alternative embodiment of the container 240, which in an embodiment of the vehicle and the internal combustion engine 10, with reference to Fig. As described in Section 1, the container 240 can be used. In this embodiment, the container 240 is arranged as a rigid container with a rectangular prismatic shape, forming and defining a plurality of chambers arranged in series between the first opening 31 and the second opening 32. In one embodiment, and as described herein, the container 240 comprises the first volumetric chamber 41, which is arranged in series with a second volumetric chamber 42, which is arranged in series with a third volumetric chamber 43, which is fluidically coupled at one end to the second port 32.In one embodiment, as shown, the first volumetric chamber 41, the second volumetric chamber 42, and the third volumetric chamber 43 are arranged as rectangular prismatic structures side by side, the first volumetric chamber 41 being separated from the second volumetric chamber 42 by a first separator 44, and the second volumetric chamber 42 being separated from the third volumetric chamber 43 by a second separator 46. The first separator 44 has a first screen 45 at a first end, and the second separator 46 has a second screen 47 at a second, opposite end. The arrangement allows a flow path 34 through the container 240 between the first opening 31 and the second opening 32, which runs in series through the first volumetric chamber 41, the second volumetric chamber 42, and the third volumetric chamber 43.

[0039] The first volumetric chamber 41 is filled with a first adsorbent 151, the second volumetric chamber 42 with a second adsorbent 152, and the third volumetric chamber 43 with a third adsorbent 153. A first actuator 161, controlled by a first control pulse 55, is also located in the first volumetric chamber 41. A second actuator 162, controlled by a second control pulse 56, is also located in the second volumetric chamber 42. A third actuator 163, controlled by a third control pulse 57, is also located in the third volumetric chamber 43. In one embodiment, a fourth actuator 164 is arranged in the second opening 32, controlled by a fourth control pulse 58.The first actuator 161, the second actuator 162, the third actuator 163 and the fourth actuator 164 (when used) are analogous to the controllable device 54, which is described with reference to . Fig. 1 is described, and the first control stimulus 55, the second control stimulus 56, the third control stimulus 57 and the fourth control stimulus 58 (if used) are analogous to the control stimulus 55 described with reference to Fig. 1 is described.

[0040] The first adsorption material 151 can be analogous to the first adsorption material 51, which is described with reference to Fig. As described in Figure 1, the first adsorbent 151 is a MOF material with a pore width that, in one embodiment, is between 2.5 nm and 5 nm, or with a pore width that, in another embodiment, is less than 5 nm. Alternatively, the first adsorbent 151 can be a flexible MOF material controlled by the first control pulse 55. Alternatively, the first adsorbent 151 can also be an activated carbon material.

[0041] The second adsorbent 152 is a MOF material with a pore width that, in one embodiment, lies between 10 nm and 40 nm. Alternatively, the second adsorbent 152 can be a MOF material configured to adsorb oxygen-containing fuel vapor components, including ethanol. Alternatively, the second adsorbent 152 can be a flexible MOF material controlled by the second control pulse 56. Alternatively, the second adsorbent 152 can also be an activated carbon material.

[0042] In one embodiment, the third adsorbent 153 is an activated carbon material. Alternatively, the third adsorbent 153 can be a flexible MOF material controlled by the third control pulse 57.

[0043] The controller 80 is operationally connected to the tank vent valve 37 and the first, second, and / or third and / or fourth control pulses 55, 56, 57, 58 when in use. The controller 80 generates the first, second, and / or third and / or fourth control pulses 55, 56, 57, 58. Each of the first, second, and / or third and / or fourth control pulses 55, 56, 57, 58 comprises a first state and a second state. The control stimuli 55, 56, 57 can be a partial pressure, an ambient temperature, a light intensity, an electrical signal, an electromagnetic signal, or a combination thereof. In one embodiment, the first, second, and / or third and / or fourth control pulses 55, 56, 57, 58 are in the form of control signals that can be actively generated by the controller 80.In such embodiments, the first, second, and / or third and / or fourth control pulses 55, 56, 57, 58 can be constant or modulated electrical voltage or current signals or electromagnetic signals. In one embodiment, the control pulses 55, 56, 57 can be generated indirectly by one or more engine operating states and / or vehicle operating states. In such embodiments, the control pulses 55, 56, 57 can be one or a combination of a partial pressure, an ambient temperature, or a light intensity. Fig. Figure 3 illustrates an example of a flexible MOF 330. The flexible MOF 330 is a hybrid organic-inorganic material constructed by linking secondary building blocks (SBUs) 310 via rigid organic ligands 320. In one embodiment, the SBU 310 comprises metal oxide clusters. The flexible MOF 330 can also be described as having interchangeable metal-containing nodes and carbon-based struts. The pore sizes and their chemical functionality can be tailored by controlling the architecture, including the adsorption of specific hydrocarbon molecules. Fig. Figure 4 shows a portion of an embodiment of the flexible MOF material, e.g., Co(bdp), in a first, collapsed state 410 and a second, expanded state 430, as well as an associated control pulse 420. The flexible MOF material can be reversibly controlled to the first, collapsed state 410 and the second, expanded state 430 in response to the control pulse 420. As shown, the flexible MOF material can be transformed to have densely arranged, small pores capable of adsorbing hydrocarbon vapor when it is brought into the first, collapsed state 410 by the control pulse 420. As shown, the flexible MOF material can also be transformed to have loosely arranged, large pores capable of desorbing hydrocarbon vapor when it is brought into the second, expanded state 430 by the control pulse 420.A sensor 415 is arranged for monitoring the flexible MOF material. The sensor 415 can be a position sensor, an electrical continuity sensor, or another device capable of detecting whether the flexible MOF material is in the first, collapsed state 410 or in the second, expanded state 430, for control and diagnostic purposes. Again referring to… Fig. In one embodiment, the vapor barrier element 90 is a flexible metal-organic framework material (MOF) that can be reversibly controlled into a first state and a second state in response to a control impulse. Alternatively, the vapor barrier element 90 can also be a metal-organic framework (MOF).

[0044] Known compositions of gasoline are a combination of alkanes (C4-C 12Gasoline consists of alkylbenzenes, indanes, and naphthalenes with boiling points of approximately 35–200 °C, and one or more oxygen-containing components such as ethanol. Regarding the composition of the mixture, gasoline can contain 55–77% saturated hydrocarbons, 9–36% aromatics, some unsaturated hydrocarbons, and 10–15% ethanol. Gasoline vapor contains highly volatile organic compounds (VVOCs), with n-butane, isobutane, n-pentane, and 2-methylbutane together comprising 60–77% by weight. The most abundant alkane in vaporized gasoline is n-butane. The headspace composition can be predicted based on the fuel composition, vapor-liquid equilibrium theory, and activity coefficients.

[0045] Fig. Figure 5 schematically shows a flowchart of a control algorithm for the evaporative emission system (“control algorithm”) 500, which can be implemented in the control unit 80 to control an embodiment of a vehicle comprising an embodiment of the internal combustion engine 10 and the evaporative emission system 30, which, with reference to Fig. The evaporative emission system 30 comprises a container 40, which is arranged to collect fuel vapors from the fuel storage system 70 and which is connected to the intake manifold 14 of the internal combustion engine 10 via a vent valve 37. The container 40 contains the first adsorbent 51 in the form of MOF material, which is arranged in the chamber 41. In one embodiment, the MOF material arranged in the chamber 41 is a flexible MOF material, e.g., as described herein. A controllable device, e.g., the controllable device 54, is connected to the MOF material. The control unit 80 is operationally connected to the controllable device 54 and the vent valve 37. The control unit 80 contains a set of instructions in the form of the control algorithm 500, which can be executed to activate the controllable device 54 and to control the vent valve 37 in response to a command to vent the container 40.The control algorithm 500 further comprises determining an activation parameter for the controllable device 54, determining a venting flow and a total venting mass, and deactivating the controllable device if the total venting mass is greater than a threshold value. The activation parameter for the controllable device 54 corresponds to the control pulse 55.

[0046] As can be seen, the concepts described here also apply to embodiments of the combustion engine 10 and the evaporative emission system 30, which are described with reference to Fig. 1 are described, which use an embodiment of the container 240, which is described with reference to Fig. 2 is described for capturing fuel vapors from the fuel storage system 70 and is fluidically connected to the intake manifold 14 of the internal combustion engine 10 via a vent valve 37. Details of the control algorithm 500 are as follows. The control algorithm 500 monitors the operation of the vehicle to detect the occurrence of a "key-on" event, i.e., an indication by the driver that he intends to operate the vehicle (502). If no key event (502)(0) occurs, the controllable device 54, and thus the first adsorbent 51 including the MOF material, is controlled to the first state via the control pulse 55 (504) to facilitate the adsorption of hydrocarbons by the first adsorbent 51. In response to a key-on event (502)(1), a container venting routine 510 is executed.The first step of the tank venting routine 510 is to determine whether a tank venting event is activated (512). This includes, as non-restrictive examples, an evaluation of the operation of the internal combustion engine 10 to determine whether it is capable of handling operation with a stream of additional hydrocarbons from the tank 40. Such an evaluation may include determining that the engine 10 is in a warm-up state, determining that an exhaust aftertreatment system is capable of handling additional hydrocarbons, etc. The venting release criteria and the associated engine operating criteria are system-specific and known.When the venting release criteria are met (512)(1), the venting valve 37 is activated to release the flow (520), and the control pulse 55 commands the operation of the controllable device 54 to control the first adsorption material 51, including the MOF material, into the second state (514) to facilitate the desorption of hydrocarbons from it. After activation of the venting valve 37, the motor operation is monitored to estimate a venting flow rate (522), and an integrated venting mass is determined by performing a time integration of the estimated venting flow rate (524). The integrated venting mass is compared to a venting mass threshold (526). Alternatively, the estimated venting flow rate can be used to determine a venting volume and compared to a venting volume threshold.Simultaneously, the control stimulus 55 is monitored to estimate or otherwise determine a quantity of activation energy supplied to the MOF material and integrated over time (516). The time-integrated quantity of activation energy supplied to the MOF material is compared to an energy threshold (518). This process continues as long as both the integrated venting mass is below the venting mass threshold (526)(0) and the time-integrated quantity of activation energy supplied to the MOF material is below the energy threshold (518)(0).If either the integrated venting mass is greater than the venting mass threshold (526)(1) or the time-integrated magnitude of the activation energy introduced into the MOF material is greater than the energy threshold (518)(1), the control pulse 55 commands the operation of the controllable device 54 to control the first adsorption material 51, including the MOF material, into the first state (530). The venting valve 37 continues to be activated to allow flow through the reservoir 40 during the switch-on process, unless other factors cause it to be deactivated.

[0047] In one embodiment, the controllable device 54 is a heating element, wherein in the first state active heating is controlled and in the second state no heating is controlled.

[0048] Fig. Figure 6 schematically shows a flowchart of a monitoring algorithm for the evaporative emission system (“monitoring algorithm”) 600, which can be executed in the controller 80 to monitor a vehicle design comprising an embodiment of the internal combustion engine 10 and the evaporative emission system 30, which, with reference to the Fig. 1, Fig. 2 and Fig. 4. The monitoring algorithm 600 is designed to detect the occurrence of a fault in the evaporative emission system 30, which comprises an embodiment of the container 40 arranged to collect fuel vapors from the fuel storage system 70 and flow-connected to the intake manifold 14 of the internal combustion engine 10 via a vent valve 37. The container 40 has the first adsorption material 51 in the form of MOF material, which is arranged in the chamber 41. In one embodiment, the MOF material arranged in the chamber 41 is a flexible MOF material, e.g., as described here. The controllable device, e.g., the device 54, is connected to the MOF material. The control unit 80 is connected to the controllable device and the vent valve 37 and communicates with various sensors via the communication link 38.The controller 80 contains an instruction set in the form of the monitoring algorithm 600.

[0049] Details of the monitoring algorithm 600 are as follows. The monitoring algorithm 600 is executed during engine operation when the enable criteria are met (602)(1). The enable criteria may include reaching selected states for engine operating parameters, the absence of faults, and other criteria. If the enable criteria are not met (602)(0), the execution of the monitoring algorithm 600 is postponed.

[0050] The monitoring algorithm 600 comprises the regular and / or periodic monitoring of inputs from vehicle-side sensors, timers, control routines, etc. (604). It is understood that one or more of the vehicle-side sensors can be replaced by an estimation model to determine the desired parameter. Inputs include, for example, signal inputs from the control pulse 55, the control signal for the vent valve 37, the engine operation from the exhaust gas sensor 19, the position sensor 415, which is arranged to monitor the flexible MOF material, MOF sensors 59, etc.

[0051] The monitoring algorithm 600 includes the execution of a variety of diagnostic monitoring algorithms to evaluate elements of the evaporative emission system 30, the tank 40, and the internal combustion engine 10. Exemplary diagnostic monitoring algorithms include a power rationality test 606, an idle / short-circuit test 608, an equipment position rationality test 610, a MOF parameter test 612, a venting rationality test 614, and / or a vapor flow rationality test 616.

[0052] The power rationality check 606 indicates whether the power consumed by the control stimulus 55, integrated over its operation, is within a permissible maximum and minimum power range. The permissible maximum and minimum power range is related to the expected power requirement for venting the vessel 40 of hydrocarbon vapor by activating the flexible MOF material via the control pulse 55. The power rationality check 606 indicates that there is no fault (630) related to the power consumed by the control stimulus 55 if the integrated power is within the permissible maximum and minimum power range (606)(1). The power rationality check 606 indicates the occurrence of a fault (620) if the integrated power is outside the permissible maximum and minimum power range (606)(0).

[0053] The open circuit / short circuit test 608 is an electrical test of the communication link elements 38 that are connected to the actuators and sensors used by the evaporative emission system 30, such as the vent valve 37, the control pulse 55, etc. The electrical test of the communication link elements 38 includes a test for the occurrence of short circuits or open circuits. The open circuit / short circuit test 608 indicates that there is no short circuit or open circuit fault (630) if no short circuits or open circuits are detected in the communication link 38 (608)(1). The open circuit / short circuit test 608 indicates a possible occurrence of a fault (620) if either a short circuit or an open circuit is detected in the communication link 38 (608)(0).

[0054] The rationality check of the device position 610 monitors the input signal of the position sensor 415, which is integrated into the flexible MOF material, to determine whether the flexible MOF material is in a position that corresponds to the command position specified by the control pulse 55. For example, when the control pulse 55 commands the flexible MOF material to the first state, the position sensor 415 indicates that the flexible MOF material has densely packed, small pores capable of adsorbing hydrocarbon vapor. When the control pulse 55 moves the flexible MOF material to the second state, the position sensor 415 indicates that the flexible MOF material has large pores capable of desorbing hydrocarbon vapor.The device position rationality check 610 indicates that there is no error related to the position of the flexible MOF material (630) if the position sensor 415 indicates that the flexible MOF material is in a position that corresponds to the command position indicated by the control pulse 55 (610)(1). The device position rationality check 610 indicates a possible occurrence of an error (620) if the position sensor 415 indicates that the flexible MOF material is in a position that does not correspond to the command position indicated by the control pulse 55 (610)(0).

[0055] The MOF parameter test 612 monitors one or more inputs from sensors and associated models to determine a MOF parameter related to the structural or electrical integrity of the flexible MOF material 51 in container 40. As described in Fig.As described in Figure 1, the MOF sensor 59 can be an electrical sensor arranged to monitor the electrical conductivity or electrical resistance across the flexible MOF material during the venting process. Alternatively, the MOF sensor 59 can be a differential pressure sensor arranged to monitor a pressure drop across the flexible MOF material during the venting process. Alternatively, the MOF sensor 59 can also be a temperature sensor arranged to monitor the temperature of the flexible MOF material during the venting process. Alternatively, the MOF sensor 59 can also comprise multiple temperature sensors arranged to monitor a temperature gradient across the flexible MOF material during the venting process.MOF parameter check 612 indicates that there is no fault related to the structural or electrical integrity of the flexible MOF material (630) if a parameter connected to a signal output of the MOF sensor 59 is within a predetermined calibrated range (612)(1). MOF parameter check 612 indicates a possible occurrence of a fault (620) if the MOF sensor 59 indicates that the flexible MOF material is outside the predetermined calibrated range (612)(0).

[0056] In one embodiment, the venting rationality check 614 monitors the time associated with a venting event. The venting time refers to the expected time required to vent the vessel 40 and may be related to feedback from the WRAF sensor 19 or other information. A venting time error may indicate a broken or blocked vent line, a leak in the system, a defect or deterioration of the flexible MOF material, etc. The venting rationality check 614 indicates that there is no fault associated with the evaporation system 30 (630) if the venting time is within a predetermined calibrated time range (614)(1). The venting rationality check 614 indicates a possible occurrence of a fault (620) if the venting time is outside the predetermined calibrated time range (614)(0).

[0057] In one embodiment, the vapor flow test 616 monitors a parameter related to the engine's air / fuel ratio control by using feedback from the exhaust gas sensor 19 during a venting process. The parameters associated with the engine's air / fuel ratio control relate to the expected adjustment of the engine's air / fuel ratio control to compensate for the flow of hydrocarbon vapor from the reservoir 40 during the venting process. The vapor flow rationality test 616 can indicate a broken or blocked vent line, a leak in the system, a defect or deterioration of the flexible MOF material, etc.The steam flow rationality test 616 indicates that there is no fault related to the evaporation system 30 (630) if the parameter associated with the control of the engine's air / fuel ratio is within a predetermined calibrated time range (616)(1). The steam flow rationality test 616 indicates a possible occurrence of a fault (620) if the venting time is outside the predetermined calibrated time range (616)(0).

[0058] The term "controller" and related terms such as microcontroller, controller, control unit, processor, etc., refer to one or more combinations of application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), electronic circuits, central processing units (CPUs), e.g., microprocessors, and associated non-transitory memory components in the form of storage devices (read-only, programmable read-only, random access, disk devices, etc.). The non-transitory memory component is capable of storing machine-readable instructions in the form of one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices, signal conditioning, buffer circuits, and other components that one or more processors can access and execute to provide the described functionality.Input / output circuits and devices include analog-to-digital converters and related devices that monitor sensor inputs, either at a preset sampling rate or in response to a triggering event. Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to sets of instructions, including calibrations and lookup tables, that can be executed by controllers. Each controller executes control routine(s) to provide the desired functionality. The routines can be executed at regular intervals, such as every 100 microseconds during normal operation. Alternatively, the routines can be executed in response to a triggering event.Communication between controllers, actuators, and / or sensors can occur via a direct wired point-to-point connection, a networked communication bus connection, a wireless connection, or another communication link. This communication involves the exchange of data signals, such as electrical signals over a conductive medium, electromagnetic signals over air, optical signals over fiber optic cables, etc. Data signals can include discrete, analog, and / or digitized analog signals representing sensor inputs, actuator commands, and communication between controllers. The term "signal" refers to a physically perceptible indicator that conveys information and can be a suitable waveform (e.g., a waveform).electrical, optical, magnetic, mechanical or electromagnetic), such as direct current, alternating current, sine wave, triangle wave, square wave, vibration and the like, which can move through a medium.

[0059] The term "model" refers to processor-based or processor-executable code and its associated calibration, which simulates the physical existence of a device or process. The terms "dynamic" and "dynamic" as used here describe steps or processes that are executed in real time and are characterized by monitoring or otherwise determining the states of parameters and regularly or periodically updating the states of the parameters during the execution of a routine or between iterations of the routine's execution.

[0060] The terms "calibration," "calibrated," and related terms refer to a result or process that correlates a desired parameter with one or more perceived or observed parameters for a device or system. A calibration as described here can be reduced to a storable parameter table, a set of executable equations, or any other suitable form that can be used as part of a measurement or control routine.

[0061] A parameter is defined as a measurable quantity that represents a physical property of a device or other element, which can be determined using one or more sensors and / or a physical model. A parameter can have a discrete value, e.g., either "1" or "0", or it can have a continuously variable value.

Claims

[1] Vehicle system comprising: an internal combustion engine (10); Evaporative emission system (30) with a container (40) arranged to collect fuel vapors from a fuel tank and connected to an intake part of the internal combustion engine (10) via a vent valve (37); wherein the container (40) defines a chamber (41) and a flexible metal-organic framework material (MOF) is arranged in the chamber (41); a controllable device (54) connected to the flexible MOF material; and a control unit (80) which is operationally connected to the controllable device (54) and the vent valve (37), wherein the control unit (80) contains a set of commands which can be executed to: Activating the controllable device (54) and controlling the vent valve (37) in response to a command to vent the container (40) into an open state, Determining an activation parameter for the controllable device (54), Determining a venting flow and a total venting mass, and Deactivating the controllable device (54) if the total venting mass is greater than a threshold value. [2] Vehicle system according to claim 1, further comprising the instruction set which is executable to deactivate the controllable device (54) when the activation parameter for the controllable device (54) is greater than a second threshold. [3] Vehicle system according to claim 1, wherein the controllable device (54) coupled to the flexible MOF material comprises a first heating element located near the flexible MOF material, wherein the instruction set executable to activate the controllable device (54) includes the instruction set executable to control the controllable device (54) into a heat-generating state. [4] Vehicle system according to claim 3, wherein the first heating element is a positive temperature coefficient (PTC) heating element, a thin-film heating element or a rod heating element. [5] Vehicle system according to claim 3, wherein the controllable device (54) includes a second heating element arranged in a flow stream near a vent opening of the container (40), wherein the control (80) operates such that it activates the second heating element in response to the command to vent the container (40). [6] Vehicle system according to claim 1, wherein the flexible metal-organic framework material (MOF) arranged in the chamber (41) of the container (40) comprises a hybrid organic-inorganic material composed by linking metal oxide clusters by rigid organic ligands, wherein the flexible MOF material is reversibly controllable in response to a control stimulus into a first, collapsed state or a second, expanded state, and wherein the control stimulus corresponds to the activation parameter for the controllable device (54). [7] Vehicle system according to claim 1, wherein the controller (80) is operable to integrate the activation parameter in order to determine an integrated activation energy parameter for the controllable device (54); and wherein the controller (80) serves to detect a fault associated with the controllable device (54) when the integrated activation energy parameter for the controllable device (54) is either greater than an upper threshold or less than a lower threshold. [8] Vehicle system according to claim 1, further comprising a sensor element arranged to monitor an element of the evaporative emission system (30) and to communicate with the control unit (80); and further comprising the instruction set executable to monitor the sensor element in order to detect a fault associated with the evaporative emission system (30). [9] Vehicle system according to claim 8, wherein the sensor element is arranged to monitor a circuit of the evaporative emission system (30), and wherein the command set is executable to detect either an open circuit or a short circuit in the circuit of the evaporative emission system (30). [10] Method for operating an in-vehicle evaporative emission system (30) with a container (40), wherein the container (40) is arranged to collect fuel vapors from a fuel tank and is fluidically connected to an intake part of an internal combustion engine (10) via a vent valve (37), wherein the container (40) defines a chamber (41) in which a flexible metal-organic framework material (MOF) is arranged, the method comprising: Controlling the vent valve (37) to an open state in response to a command to vent the container (40); Activating a controllable device (54) connected to the flexible MOF material; Determining an activation parameter for the controllable device (54), Determining a venting flow, Integrating the venting flow to determine a total venting mass, and Deactivating the controllable device (54) if the total venting mass is greater than a threshold value.

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