VAPOR CAPTURE ELEMENT FOR AN AIR INTAKE SYSTEM OF AN INTERIOR POWER ENGINE

Abstract

Air intake system (20) for an internal combustion engine (10), comprising the following: a vapor separation element (50) arranged in an inner part of an air inlet system (20), and a control (40); wherein the vapor separation element (50) is made of a flexible metal-organic framework material (51), MOF, wherein the flexible MOF material (51) is reversibly controllable; wherein the control unit (40) is operatively connected to the vapor separation element (50); wherein the control (40) generates a control pulse (52) which is transmitted to the vapor separation element (50), wherein the control pulse (52) comprises a first state and a second state; wherein the flexible MOF material (51) is configured to adsorb hydrocarbon vapor in response to the control pulse (52) being in the first state; and wherein the flexible MOF material (51) is configured to desorb hydrocarbon vapor when the control pulse (52) is in the second state.

Description

INTRODUCTION

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

[0002] The new regulations on evaporative emissions from vehicles require the control of emissions of substances, especially hydrocarbons, from the vehicle under various operating conditions. For example, when the engine is shut down, volatile hydrocarbons from various sources can accumulate in the air intake system. There is a risk that these hydrocarbons will escape into the atmosphere when the engine is shut down if they are not captured.

[0003] There is a need for an improved method, apparatus and / or system for capturing volatile hydrocarbons that may accumulate in the air intake system.

[0004] WO 2010 144 360 A2 discloses a method for adhering a particulate material, such as a hydrocarbon adsorption material and / or a catalytic material, to a plastic surface, and products comprising the adhered material.

[0005] "A. SCHNEEMANN; V. BON; I. SCHWEDLER: "Flexible metal-organic frameworks". Chem. Soc. Rev.. No. 43. 2014. pp. 6062 to 6096 discloses details on metal-organic frameworks.

[0006] US 7 553 352 B2 relates to a method for absorbing and / or storing gases, in which the gas to be stored is brought into contact with an electrochemically produced metal-organic framework material under conditions suitable for absorbing the gas, with absorption of the gas, and optionally the conditions are subsequently changed so that the stored gas is released. DESCRIPTION

[0007] The object of the invention is to capture volatile hydrocarbons that can accumulate in the air intake system.

[0008] The problem is solved with an air intake system according to claim 1.

[0009] The concepts described herein provide a vapor capture element disposed in an air intake system of an internal combustion engine for controlling evaporative emissions. The vapor capture element is disposed in an internal portion of an air intake system for an internal combustion engine. The vapor capture element is made from a flexible metal-organic framework (MOF) material, wherein the flexible MOF material is a bistable material that can be reversibly controlled to either a first state or a second state in response to a control pulse. The flexible MOF material is capable of adsorbing hydrocarbon vapor when in the first state and desorbing the hydrocarbon vapor when in the second state. The flexible MOF material is capable of adsorbing and desorbing hydrocarbon vapors in the air intake system.The vapor deposition element is tunable to a specific system and can be actively controlled during operation. Flexible MOFs are capable of changing their pore size and / or other adsorption and desorption capabilities in response to an external stimulus to selectively adsorb and desorb hydrocarbon vapor components in the air intake system.

[0010] One aspect of the disclosure includes that the control pulse is a partial pressure, an ambient temperature, a light intensity, an electrical signal, or an electromagnetic signal.

[0011] Another aspect of the disclosure includes that the flexible MOF material is configured to transform into densely arranged, small pores capable of adsorbing the hydrocarbon vapor in the first state, and that the flexible MOF material is configured to transform into loosely arranged, large pores capable of desorbing the hydrocarbon vapor in the second state.

[0012] Another aspect of the disclosure includes that the flexible MOF material is a hybrid organic-inorganic material assembled by connecting secondary building blocks using rigid organic ligands.

[0013] Another aspect of the disclosure includes that the secondary building blocks are metal oxide clusters.

[0014] Another aspect of the disclosure includes that the flexible MOF material is one of the following: MIL-53 Al (aluminum terephthalate MOF), MIL-88 series (iron(III) dicarboxylate MOFs), ZIF-8 (zeolitic imidazolate framework of zinc ions coordinated by four imidazolate rings), Co(bdp) (cobalt-based MOF with bdp 2- = 1,4-benzenedipyrazolate linker.

[0015] Another aspect of the disclosure includes the vapor deposition element disposed on an inner wall of an air cleaner housing.

[0016] Another aspect of the disclosure includes that the vapor deposition element is arranged upstream of an air filter element.

[0017] Another aspect of the disclosure includes that the vapor deposition element is arranged downstream of an air filter element.

[0018] Another aspect of the disclosure includes the vapor capture element having a planar surface, wherein the vapor capture element is disposed in the inner part of the air intake system with an orientation of the planar surface parallel to a direction of an air flow path in the air intake system.

[0019] Another aspect of the disclosure includes an air intake system for an internal combustion engine, comprising a vapor deposition element disposed within an internal portion of an air intake system and a controller. The vapor deposition element is made of a flexible metal-organic framework (MOF) material, wherein the flexible MOF material is reversibly controllable. The controller is operatively connected to the vapor deposition element and generates a control pulse that is transmitted to the vapor deposition element. The control pulse includes a first state and a second state. The flexible MOF material is configured to adsorb hydrocarbon vapor when the control pulse is in the first state and to desorb hydrocarbon vapor when the control pulse is in the second state.

[0020] The above summary is not intended to describe every possible embodiment or aspect of the present disclosure. Rather, the above summary is intended to illustrate some of the novel aspects and features disclosed herein. The above features and advantages, as well as other features and advantages of the present disclosure, will be readily apparent from the following detailed description of representative embodiments and modes for carrying out the present disclosure, taken in conjunction with the accompanying drawings and the claims. BRIEF DESCRIPTION OF THE CHARACTERS

[0021] One or more embodiments will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 schematically shows parts of an internal combustion engine and an evaporative emission system with a vapor deposition element made of a flexible metal-organic framework (MOF) material, according to the disclosure. Fig. 2 schematically shows a portion of an air filter system including a filtered air housing of an air filter housing and a vapor deposition element made of a flexible MOF material, according to the disclosure. Fig. 3 shows an example of a flexible MOF material according to the disclosure. Fig. 4 depicts a portion of an exemplary flexible MOF material in a first collapsed state and a second expanded state, as well as an associated control pulse, in accordance with the disclosure.

[0022] The accompanying drawings are not necessarily to scale and may present a somewhat simplified representation of various preferred features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes. Details associated with such features will be determined in part by the particular intended application and environment of use. DETAILED DESCRIPTION

[0023] The components of the embodiments described and illustrated herein can be arranged and configured in a variety of different configurations. Therefore, the following detailed description is not intended to limit the scope of the claimed disclosure, but is merely representative of possible embodiments thereof. Moreover, while numerous specific details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed herein, some embodiments may be practiced without some of these details. Also, in the interest of clarity, detailed descriptions of certain technical details known in the art have been omitted so as not to unnecessarily obscure the disclosure.Furthermore, the disclosure as illustrated and described herein may be practiced without any element not specifically disclosed herein. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals designate like or corresponding parts and features.

[0024] As used herein, the term “system” 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.

[0025] As used herein, the term "upstream" and related terms refer to elements located toward the origin of a flow relative to a specified location, and the term "downstream" and related terms refer to elements located away from a flow origin relative to a specified location.

[0026] With reference to the figures, in which like reference numerals correspond to the same or similar components in the different figures, the Fig. 1 and Fig. 2 schematically illustrates a portion of a multi-cylinder internal combustion engine 10 and a fuel storage system 30 for a vehicle, in accordance with the embodiments disclosed herein, including one embodiment of a vapor deposition element 50. The vehicle may include, 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 off-road vehicle, a personal transporter, a robot, and the like, in order to fulfill the purposes of this disclosure.

[0027] The illustrated part of the internal combustion engine 10 comprises a single combustion chamber 12 which is fluidly connected to an air intake system 20 and an intake manifold 14. The elements of the internal combustion engine 10 include a fuel injector 13, a throttle valve 15, and an airflow sensor 16. The air intake system 20 comprises a fresh air inlet 21 connected to the intake manifold 14 via a fresh air line 22, an air filter housing 23, and an intake manifold line 27. The air filter housing 23 includes 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.The vapor separation element 50 is 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.

[0028] The internal 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 used with another form of fuel injection, such as, but not limited to, a direct injection system. Furthermore, the concepts described here can also be applied to a compression-ignition engine.

[0029] The fuel storage system 30 includes a fuel storage tank 31 and an evaporative canister 34. The fuel storage system 30 supplies fuel via a fuel pump to an engine fuel distribution system connected to the engine's fuel injectors, including the depicted fuel injector 13. The fuel storage tank 31 is connected to the evaporative storage canister 34 via a vapor line 35. The evaporative storage canister 34 is connected to the air intake system 20 at port 17 via a vent line 36 and a vent valve 37. The vent line 36 is fluidly connected to the air intake system 20 on the filtered air side 29 downstream of the throttle body 15 at or near the intake manifold 14.

[0030] A controller 40 is arranged to control the operation of the internal combustion engine 10, including the control of the vent valve 37. The controller 40 is also in communication with and / or operatively connected to the vapor separation element 50, whereby the controller 40, in one embodiment, transmits a control pulse 52 to the vapor separation element 50.

[0031] The vapor deposition element 50 is made from a flexible metal-organic framework (MOF) 51 capable of adsorbing and desorbing hydrocarbon material. In one embodiment, the vapor deposition element 50 is formed by assembling the flexible MOF material 51 with a binder material. In one embodiment, the vapor deposition element 50 is formed by applying the flexible MOF material 51 to a substrate. In one embodiment, the vapor deposition element 50 is formed by integrating the flexible MOF material 51 into a thin film. In one embodiment, the vapor deposition element 50 is formed by enclosing the flexible MOF material 51 in a sealed bag, wherein the sealed bag is made from a material that is porous to hydrocarbons.

[0032] In one embodiment, the vapor deposition element 50 is formed as a plate with a flat, planar surface. Alternatively, the vapor deposition element 50 may also be formed as a plate with a tubular, convoluted, or corrugated surface contour. Alternatively, the vapor deposition element 50 may be arranged in a honeycomb-shaped surface. In one embodiment, the honeycomb-shaped surface may be oriented orthogonally to the air flow direction. Alternatively, the vapor deposition element 50 may be arranged as a plate with a discontinuous surface contour, e.g., in a W-shape, V-shape, L-shape, I-shape, box-shape, etc.

[0033] The vapor separation element 50 is arranged in an inner part of the air filter housing 23 on the filtered air side 29, i.e., downstream of the air filter element 25. The vapor separation element 50 can be formed as a flat, planar plate arranged in the housing 26 of the air filter housing 23 for filtered air and attached to a surface, for example, an inner wall. This arrangement is shown in Fig. 2. In one embodiment, the vapor separation element 50 may be arranged as a flat, planar plate that is arranged in and secured to the air filter element 25 in the filtered air housing 26 of the air filter housing 23. This arrangement is shown in Fig. 1. Alternatively, the vapor separation element 50, when arranged with a flat surface, may be arranged in the inner part of the air intake system 20 on the filtered air 29 side, i.e., downstream of the air filter element 25 and with the flat orientation parallel to a direction of an air flow path in the air intake system 20. In this embodiment, the vapor separation element 50 may be arranged centrally in the filtered air housing 26 of the air filter housing 23 or in the intake manifold duct 27. Alternatively, there may be multiple vapor separation elements 50 arranged in individual ducts of the intake manifold 14.

[0034] The air intake system 20 for the internal combustion engine 10 includes the vapor deposition element 50, which is arranged in an inner part of the air intake system 20, and the controller 40. The vapor deposition element 50 is made of the flexible MOF material 51, wherein the flexible MOF material 51 is bistable and reversibly controllable.

[0035] The controller 40 is operatively connected to the vapor deposition element 50 via the control pulse 52. The controller 40 generates the control pulse 52, which is passed to the vapor deposition element 50. The control pulse 52 includes a first state and a second state. In one embodiment, an actuator 54 is integrated into the vapor deposition element 50 or disposed proximate the vapor deposition element 50 and is controlled to either the first state or the second state in response to the control pulse 52. In one embodiment, the actuator 54 is an electrically resistive substrate, e.g., made of carbon, on which the flexible MOF material 51 is deposited, and can be controlled to either an on state or an off state in response to the control pulse 52 to control the vapor deposition element 50.In one embodiment, the actuator 54 is an electrically operated heating element located near the flexible MOF material 51 and can be controlled to either an on or off state in response to the control pulse 52 to control the vapor deposition element 50.

[0036] The flexible MOF material 51 has the properties of frame flexibility and dynamic response, which distinguishes it from other porous materials such as zeolites and activated carbons. The flexible MOF material 51 has the intrinsic ability to exhibit various structural transformations or dynamic behaviors in response to the control impulse 52.

[0037] Flexible MOF material 51 is a class of MOF materials that exhibit dynamic changes in pore dimensions in response to external stimuli. Depending on the design types and features, flexible MOF material 51 can exhibit various types and magnitudes of structural dynamics. These include expansion and contraction of pore diameter, also referred to as the breathing mechanism. The breathing mechanism can be triggered by external chemical stimuli, such as the adsorption, desorption, and exchange of guests. Instead, the breathing mechanism can be triggered by external physical stimuli, such as changes in temperature, light, and / or pressure.

[0038] The flexible MOF material 51 is configured to transform into densely arranged, small pores capable of adsorbing the hydrocarbon vapor when the control pulse 52 is in the first state. Volatile hydrocarbon vapor contained in the filtered air side 29 of the air intake system 20 can precipitate on the vapor deposition element 50 and / or be adsorbed by the flexible MOF material 51 when the engine is off and the flexible MOF material 51 is controlled to the first state by the control pulse.

[0039] The flexible MOF material 51 is configured to transform into loosely arranged, large pores that can desorb hydrocarbon vapor when the control pulse 52 is in the second state. The hydrocarbon vapor adsorbed by the flexible MOF material 51 during an engine off-state can be desorbed from the flexible MOF material 51 during an on-state when the flexible MOF material 51 is controlled to the second state by the control pulse 52.

[0040] The flexible MOF material 51 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 composed of zinc ions coordinated by four imidazolate rings; and Co(bdp) is a cobalt-based MOF with bdp. 2-= 1,4-benzenedipyrazolate linker.

[0041] Fig. Figure 3 depicts an example of a flexible MOF 330. The flexible MOF 330 is a hybrid organic-inorganic material constructed by connecting 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.

[0042] Fig. 4 depicts a portion of one embodiment of the flexible MOF material, e.g., Co(bdp), in a first, collapsed state 410 and a second, expanded state 410, and an associated control pulse 420. The flexible MOF material can be reversibly controlled to a first state and a second state in response to the control pulse 420. As illustrated, the flexible MOF material can be transformed to have densely arranged, small pores capable of adsorbing hydrocarbon vapor when commanded to the first, collapsed state 410 by the control pulse 420. As illustrated, the flexible MOF material can be transformed to have loosely arranged, large pores capable of desorbing hydrocarbon vapor when commanded to the second, expanded state 430 by the control pulse 420.

[0043] The flexible MOF material 51 may, in one embodiment, be pressure-sensitive, light-sensitive, heat-sensitive, or a combination thereof (see Fig. 1). The flexible MOF material can instead be designed to respond to mechanical deformation.

[0044] The vapor deposition element 50 is connected to a control pulse 52. The control pulse 52 may be a partial pressure, an ambient temperature, a light intensity, an electrical signal, an electromagnetic signal, or a combination thereof.

[0045] In one embodiment, the control pulse 52 is in the form of a control signal that can be actively generated by the controller 40. In such embodiments, the control pulse 52 can be a constant, modulated, or pulse-width-modulated electrical voltage or current signal, or an electromagnetic signal.

[0046] In one embodiment, control pulse 52 is generated indirectly by one or more engine operating conditions and / or vehicle operating conditions. In such embodiments, control pulse 52 may be one or a combination of a partial pressure, an ambient temperature, or a light intensity.

[0047] The vapor deposition element 50 comprises a flexible metal-organic framework (MOF) 51.

[0048] The flexible MOF material 51 is reversibly controllable into a first state and a second state in response to the control pulse 52.

[0049] The flexible MOF material 51 is configured to adsorb hydrocarbon vapor when controlled to the first state and to desorb hydrocarbon vapor when controlled to the second state.

[0050] Flexible MOFs have the ability to exhibit various structural transformations or dynamic behaviors in response to external stimuli. Flexible MOFs can store a larger amount of hydrocarbon vapor than similarly sized (by volume) activated carbon devices.

[0051] Through a suitable design, the HC adsorber using the flexible MOF material 51 and located in the air intake system can rapidly adsorb or desorb hydrocarbon vapors in response to the control pulse 52. Compared to activated carbon-based HC adsorbers, the adsorber would also exhibit lower settling, i.e., a permanent loss of vapor absorption. The flexible MOF material has densely arranged, small pores capable of adsorbing hydrocarbon vapor in the first state, and the flexible MOF material has loosely arranged, large pores capable of desorbing hydrocarbon vapor in the second state.

[0052] Gasoline compounds are a combination of alkanes (C4-C 12 ) and aromatics (alkylbenzenes, indanes, naphthalenes) in the boiling range of approximately 35-200°C and one or more oxygenated components such as ethanol. Regarding blend composition, 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 accounting for 60-77% by weight. The most abundant alkane in vaporized gasoline is n-butane. The headspace composition can be predicted from the fuel composition, vapor-liquid equilibrium theory, and activity coefficients.

[0053] When handling a gas mixture, the different physical properties of the individual components, such as size, shape, polarization, binding energy, and diffusion kinetics, must be considered. The effective reversible adsorption and desorption of the gas mixture on an adsorbent can be compromised by the presence of certain components. The stability of the adsorbent during adsorption-desorption cycles is crucial for vehicle applications, as it influences the service life of an evaporative emission system. For application in an evaporative emission system, adsorbents are sought whose pore size distribution is tailored to the molecules to be adsorbed. Activated carbon traditionally has a broad pore size distribution, whereas MOFs theoretically have uniform pore structures with narrow pore size distributions.

[0054] The use of a flexible MOF as described here allows the tuning of the pore size for adsorption and desorption to achieve the desired properties for the selective adsorption and desorption of desired components of a gas mixture, e.g., VVOCs such as n-butane.

[0055] The design of an adsorbent requires a comprehensive understanding of the adsorbent structure, including pore size / shape and other adsorbate properties. In this embodiment, the adsorbates are hydrocarbon molecules that adhere to the surface through weak attractive interactions called van der Waals forces. Adsorption occurs in pores whose diameter is approximately twice the molecular diameter of the molecule to be adsorbed, so the pore size distribution in the adsorbent is a crucial factor. These are the properties of the adsorbate required to better develop the material or combination of materials for adsorbing the molecules contained in the headspace composition.The flexible MOF design best suited for butane adsorption has, in one embodiment, a pore size of 2-2.5 nm, based on a correlation between the adsorption capacity of n-butane and the previously mentioned pore properties.

[0056] Another material property that can affect the adsorption uptake of adsorbates is the presence of open metal sites. In some MOFs, the metal centers are bound in a specific coordination environment, with the cation at the center being open and accessible to the adsorbed gas molecules. Unsaturated metal sites have been shown to improve certain adsorbate affinities compared to non-open metals.

[0057] The pore size is chosen so that the adsorbate molecules can easily diffuse out of the pore network and be desorbed. Pores that are potentially too small are undesirable, as they are likely to trap large molecules, leading to a decrease in storage capacity over time.

[0058] The term “controller” and related terms such as microcontroller, controller, control unit, processor, etc. refer to one or various combinations of application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), electronic circuits, central processing units, e.g.

[0059] Microprocessors and associated non-transitory memory components in the form of memory and storage devices (read-only, programmable read-only, random access, hard 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 can be accessed and executed by one or more processors to provide the described functionality. Input / output circuits and devices include analog-to-digital converters and related devices that monitor inputs from sensors, where such inputs are monitored at a preset sampling frequency or in response to a triggering event.Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to sets of instructions executable by controllers, including calibrations and lookup tables. Each controller executes control routine(s) to provide desired functionality. The routines may be executed at regular intervals, such as every 100 microseconds during ongoing operation. Alternatively, the routines may 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. Communication involves the exchange of data signals, such as electrical signals over a conductive medium, electromagnetic signals over air, optical signals over fiber optics, etc.Data signals can include discrete, analog, and / or digitized analog signals representing inputs from sensors, actuator commands, and communication between controllers. The term "signal" refers to a physically perceptible indicator that conveys information and can be any suitable waveform (e.g., electrical, optical, magnetic, mechanical, or electromagnetic), such as DC, AC, sine wave, triangular wave, square wave, vibration, and the like, capable of propagating through a medium.

[0060] The detailed description and the drawings or figures are supportive and descriptive of the present teachings, but the scope of the present teachings is defined solely by the claims. While some of the best modes and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments for carrying out the present teachings are defined in the claims.

Claims

[1] Air intake system (20) for an internal combustion engine (10), comprising: a vapor separation element (50) arranged in an internal part of an air intake system (20) and a controller (40); wherein the vapor deposition element (50) is made of a flexible metal-organic framework material (51), MOF, wherein the flexible MOF material (51) is reversibly controllable; wherein the controller (40) is operatively connected to the vapor deposition element (50); wherein the controller (40) generates a control pulse (52) that is transmitted to the vapor deposition element (50), the control pulse (52) comprising a first state and a second state; wherein the flexible MOF material (51) is configured to adsorb hydrocarbon vapor in response to the control pulse (52) being in the first state; and wherein the flexible MOF material (51) is configured to desorb hydrocarbon vapor when the control pulse (52) is in the second state.

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