阅读说明：本技术 用于车载按需十六烷和按需辛烷的基于吸附的燃料系统 (Adsorption-based fuel system for on-board cetane on demand and octane on demand ) 是由 伊萨姆·扎基·哈马德 伊曼·阿卜杜勒哈基姆·A·M·托拉 艾默尔·A·阿米尔 庄俊锡 于 2019-01-28 设计创作，主要内容包括：本发明公开了一种车辆推进系统、一种车辆燃料系统以及一种操作内燃机的方法。构成所述燃料系统的一部分的分离单元包含一个或多个基于吸附剂的室,使得所述分离单元可以选择性地接收车载燃料的至少一部分并将其分离成辛烷增强的组分和十六烷增强的组分。吸附质的再生是通过与现有系统基础设施之间的热交换关系进行的。可以使用控制器来确定所述内燃机的特定操作状况,使得能够将所述车载燃料传送到所述内燃机内的一个或多个燃烧室,而无需首先通过所述分离单元,或者在所述内燃机可能需要富辛烷或富十六烷混合物的情况下改为传送到所述分离单元,其中从所述分离单元中获取的被吸附部分和剩余部分可以存储在单独的箱中,以便稍后在所述燃烧室内混合和使用。(A vehicle propulsion system, a vehicle fuel system and a method of operating an internal combustion engine are disclosed. A separation unit forming a portion of the fuel system includes one or more adsorbent-based chambers such that the separation unit can selectively receive at least a portion of the on-board fuel and separate it into an octane-enhanced component and a cetane-enhanced component. Regeneration of the adsorbate is by heat exchange relationship with the existing system infrastructure. A controller may be used to determine specific operating conditions of the internal combustion engine such that the on-board fuel can be delivered to one or more combustion chambers within the internal combustion engine without first passing through the separation unit, or instead to the separation unit in the event that the internal combustion engine may require an octane-rich or cetane-rich mixture, wherein the adsorbed and remaining portions obtained from the separation unit may be stored in separate tanks for later mixing and use within the combustion chambers.)

1. A vehicle propulsion system, comprising:

an internal combustion engine including a combustion chamber;

a fuel system for converting an on-board fuel into an octane-rich component and a cetane-rich component, the fuel system comprising:

a fuel supply tank for containing the vehicle-mounted fuel;

a fuel conduit in fluid communication with the fuel supply tank;

a separation unit comprising at least one adsorbent-based chamber, the separation unit in fluid communication with the fuel supply tank through the fuel conduit, wherein the separation unit is configured to selectively receive and separate at least a portion of the on-board fuel into an adsorbate and a remainder;

a heat exchanger cooperating with the separation unit and configured to selectively deliver residual thermal energy generated by operation of the internal combustion engine to the at least one sorbent-based chamber to heat the adsorbate formed thereon to produce a vaporized desorbent;

a first product tank for selectively receiving and containing the vaporized desorbent; and

a second product tank for selectively receiving and containing the remainder;

a plurality of sensors configured to acquire operating parameters associated with the internal combustion engine and the fuel system; and

a controller cooperating with the internal combustion engine, a sensor, and a fuel system and configured to determine whether the internal combustion engine is in a first operating condition or a second operating condition, such that when the controller determines that the internal combustion engine is in the first operating condition, the controller is configured to direct a flow of a portion of the vehicle-mounted fuel to the combustion chamber without first passing through the separation unit, and when the controller determines that the internal combustion engine is in the second operating condition, the controller is configured to direct a flow of a portion of the vehicle-mounted fuel to the separation unit.

2. The system of claim 1, wherein the at least one sorbent-based chamber comprises a plurality of sorbent-based chambers.

3. The system of claim 2, wherein the controller is configured to direct:

delivering the on-board fuel to a first one of the adsorbent-based chambers to produce one of the adsorbate or the remainder thereon;

receiving residual thermal energy from the heat exchanger to a second one of the sorbent-based chambers such that one of the adsorbate or residue produced thereon is vaporized;

delivering vaporized adsorbate or remainder to at least one of the first product tank, the second product tank and the combustion chamber;

then:

delivering the on-board fuel to the second one of the adsorbent-based chambers to produce one of the adsorbate or the remainder thereon;

receiving residual thermal energy from the heat exchanger to the first of the sorbent-based chambers such that one of the adsorbate or residue produced thereon is vaporized; and

transferring the vaporized adsorbate or remainder to at least one of the first product tank, the second product tank and the combustion chamber.

4. The system of claim 3, wherein the controller switches adsorption of the on-board fuel from one of the first and second of the adsorbent-based chambers to the other of the first and second of the adsorbent-based chambers based on at least one of:

detecting saturation of one or the other of the sorbent-based chambers;

after a predetermined amount of time has elapsed; and

after the predetermined minimum temperature is reached.

5. The system of any of claims 1-4, wherein the first operating condition of the engine corresponds to at least one of:

an engine temperature indicative of at least one of a cold start condition and a warm-up condition, and further wherein the second operating condition of the engine corresponds to an engine temperature exceeding a cold start engine temperature and a warm-up engine temperature; and

the amount of fuel contained in at least one of the first and second product tanks is below a threshold level of octane-rich fuel or cetane-rich fuel, respectively, and further wherein the second operating condition of the engine corresponds to an engine temperature that exceeds a cold start engine temperature and a warm-up engine temperature.

6. The system of any of claims 1-4, wherein the vaporized desorbent is coupled to the fuel supply tank by a portion of the fuel conduit such that at least a portion of the vaporized desorbent is condensed upon thermal communication between the vaporized desorbent and the fuel supply tank.

7. A vehicle fuel system for converting an on-board fuel into an octane-rich component and a cetane-rich component, the fuel system comprising:

a fuel supply tank for containing the vehicle-mounted fuel;

a fuel conduit in fluid communication with the fuel supply tank;

a separation unit comprising at least one adsorbent-based chamber, the separation unit in fluid communication with the fuel supply tank through the fuel conduit, wherein the separation unit is configured to selectively receive and separate at least a portion of the on-board fuel into an adsorbate and a remainder;

a heat exchanger cooperating with the separation unit and configured to selectively deliver residual thermal energy generated by operation of the internal combustion engine to at least one sorbent-based chamber to vaporize the adsorbate or residue formed thereon;

a first product tank for selectively receiving and containing vaporized adsorbate or a condensed form of the vaporized adsorbate;

a second product tank for selectively receiving and containing condensed remainder;

a plurality of sensors configured to acquire operating parameters associated with operation of the fuel system and internal combustion engine; and

a controller cooperating with at least one of the fuel supply tank, fuel conduit, separation unit, heat exchanger, first and second product tanks, and sensor, and configured to determine an internal combustion engine operating condition such that when the controller determines a first operating condition, the controller is configured to direct a flow of a portion of the on-board fuel to such engine without first passing through the separation unit, and when the controller determines a second operating condition, the controller is configured to direct a flow of a portion of the on-board fuel to the separation unit.

8. A method of operating an internal combustion engine, the method comprising:

configuring a fuel system to include a fuel supply tank for containing on-board fuel, a separation unit, a heat exchanger, a first product tank, and a second product tank that cooperate with one another through a fuel conduit and in response to direction provided by a controller;

determining an operating condition of the internal combustion engine using the controller;

using the controller to direct a flow of a portion of the on-board fuel to a combustion chamber without first passing through the separation unit when the internal combustion engine is in a first operating condition; and

using the controller to direct a flow of a portion of the on-board fuel to the separation unit such that adsorbate accumulates on a surface of at least one chamber of the separation unit when the internal combustion engine is in a second operating condition.

9. The method of claim 8, further comprising delivering a portion of fuel containing the adsorbate to the combustion chamber independently of a portion of fuel containing the remainder during a compression ignition mode of engine operation.

10. The method of claim 8, wherein the portion of fuel containing the adsorbate is introduced to the combustion chamber via direct injection during a portion of a compression stroke.

11. The method of claim 8 wherein the remainder-containing fuel portion is introduced to the combustion chamber via direct injection during a portion of a compression stroke.

12. The method of claim 8 wherein the fuel portion containing said adsorbate is introduced into said combustion chamber during a portion of an intake stroke via port fuel injection with complete mixing with intake air, and further wherein the fuel portion containing the remainder is introduced into said combustion chamber during a portion of a compression stroke via direct injection.

13. The method of claim 8 wherein the fuel portion containing the adsorbate is introduced via direct injection during a portion of a compression stroke, further wherein the fuel portion containing the remainder is introduced via direct injection near top dead center movement of a piston reciprocating within the combustion chamber.

14. A method according to any one of claims 8 to 13, wherein the at least one chamber comprises a plurality of chambers such that when the adsorbate accumulates on a surface of a first chamber, heat from the heat exchanger is provided to a second chamber to desorb a previously adsorbed adsorbate located thereon.

15. The method of claim 14, wherein the controller instructs the heat exchanger to cause one of the first and second chambers to alternately receive a substantial amount of heat sufficient to desorb a previously adsorbed adsorbate located thereon.

Background

The present disclosure relates generally to a vehicle fuel system for selectively separating on-board fuel into octane-rich and cetane-rich components, and more particularly to such a system that facilitates thermal balancing as part of such on-board fuel separation in a manner that reduces the size, weight, and complexity associated with such fuel separation activities.

Disclosure of Invention

In the field of Internal Combustion Engines (ICEs) for vehicle propulsion, the four-cycle variant (with its intake, compression, combustion and exhaust strokes) is most commonly used, with combustion typically being effected by a spark-ignition (SI) or compression-ignition (CI) mode of operation. In SI-based mode, a mixture of air and fuel (typically octane-rich gasoline) is introduced into the combustion chamber for compression and subsequent ignition by a spark plug. In CI-based engines, fuel (typically cetane-rich diesel fuel) is introduced into a combustion chamber where air is already present in a highly compressed form, so that the increased temperature within the chamber with accompanying pressure increase auto-ignites the fuel. In both modes, the CI mode tends to operate at higher efficiency, while the SI mode tends to operate at lower emissions.

Various engine concepts or configurations may mimic the relatively low emissions of the SI operating mode while satisfying the high efficiency operation of the CI operating mode. Such concepts are variously named and include gasoline direct injection compression ignition (GDCI), Homogeneous Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI), and others. In one form, a single fuel may be used, while in other forms, multiple fuels of different reactivity, typically in selective octane-enriched or cetane-enriched forms, may be introduced. While Octane On Demand (OOD) or hexadecane on demand (COD) may be implemented as a means to fuel these engines, such activities may be fraught with problems. For example, having the respective octane-enriched or cetane-enriched fractions in a pre-separated form involves the use of at least two on-board storage tanks and associated delivery conduits in parallel. In addition, the time and complexity associated with vehicle refueling activities in this situation render the possibility of operator error significant. Likewise, OOD or COD generation when a single market fuel is onboard may require distillation or membrane-based pervaporation (pervaporation) activities that are accompanied by significant increases in the size, weight, and overall complexity of onboard fuel reformation infrastructures. These difficulties are particularly acute as they relate to achieving the heat balance associated with the base fuel enrichment activities. As such, a simplified method of integrating such infrastructure into an on-board fuel separation system is warranted.

According to one embodiment of the present disclosure, a vehicle propulsion system is disclosed. The propulsion system includes an ICE having a combustion chamber, and a fuel system for converting an on-board fuel into an octane-rich component and a cetane-rich component. The fuel system includes a supply tank for holding on-board fuel, a fuel conduit in fluid communication with the supply tank, a separation unit, a heat exchanger, and first and second product tanks. The separation unit includes one or more adsorbent-based chambers such that the separation unit can selectively receive at least a portion of the on-board fuel and separate it into an adsorbate and a remainder. The heat exchanger cooperates with the separation unit to selectively deliver residual thermal energy generated by operation of the ICE to at least one adsorbent-based chamber to heat and subsequently vaporize (i.e., desorb) at least some of the adsorbate. In one form, a first product tank may be used to hold the desorbent and a second product tank may hold the remainder. The controller may be configured to determine an operating condition of the ICE, direct a flow of a portion of the on-board fuel to the combustion chamber without first passing through the separation unit if in the first operating condition, or direct a flow of a portion of the on-board fuel to the separation unit if in the second operating condition.

In accordance with another embodiment of the present disclosure, a fuel system is disclosed. The fuel system includes a supply tank for holding on-board fuel, a fuel conduit in fluid communication with the supply tank, a separation unit, a heat exchanger, and first and second product tanks, while a controller in cooperation with the ICE and the fuel system is configured to determine whether the ICE is in a first operating condition or a second operating condition, such that when the controller determines that the ICE is in the first operating condition, the controller is configured to direct a flow of a portion of the on-board fuel to the combustion chamber without first passing through the separation unit, and when the controller determines that the ICE is in the second operating condition, the controller is configured to direct a flow of a portion of the on-board fuel to the separation unit.

According to yet another embodiment of the present disclosure, a method of operating an internal combustion engine is disclosed. The method includes configuring a fuel system having an on-board fuel supply tank, a separation unit, a heat exchanger, first and second product tanks, and a fuel conduit. A controller provides guidance to at least some of the other components so that the controller can determine operating conditions of the ICE and then direct a flow of a portion of the on-board fuel to a combustion chamber of the engine or the separation unit based on engine operating conditions. In the determined first engine condition, on-board fuel flow does not interact with the separation unit, but rather enters the combustion chamber for immediate use by the engine. Under the determined second engine condition, an on-board fuel flow interacts with the separation unit such that an adsorbent portion of the on-board fuel collects on a surface of at least one of the plurality of chambers of the separation unit.

Drawings

The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

FIG. 1 illustrates a partial cross-sectional view of a vehicle and engine in accordance with one or more embodiments shown or described;

FIG. 2 illustrates a simplified cross-sectional view of a cylinder of the engine of FIG. 1 along with a controller in accordance with one or more embodiments shown or described;

FIG. 3 illustrates a simplified view of an on-board fuel separation system in accordance with one or more embodiments shown or described;

FIG. 4 illustrates the adsorption rate of highly aromatic fuel compounds to specific adsorbent functional groups that may be used in the on-board fuel separation system of FIG. 3; and is

Fig. 5 illustrates exemplary adsorbate flow rates at three separate time periods in accordance with one or more embodiments shown or described.

Detailed Description

In the present disclosure, an adsorption-based separation system may be used to separate the on-board fuel into an OOD stream or a COD stream by utilizing one of two specific mechanisms: (1) employing different functional groups that attract specific adsorbates (such as aromatics, cyclics, and optionally oxygenates) present in an on-board fuel supply; (2) molecular screening is used to selectively deliver certain smaller (that is, linear) molecules while retaining the larger (that is,branched) molecules. Examples of the first type of adsorbent comprise activated carbon, silica and alumina and generally some types of zeolites and functionalized porous materials, while examples of the second type comprise zeolites, metal-organic frameworks and structured porous materials. In this context, when the fuel is isooctane (2,2, 4-trimethylpentane, C)₈H₁₈) Or equivalent antiknock agent, is greater than the concentration of fuel from a readily available market that has taken one or more separation activities, then the fuel is considered octane-rich. For example, for so-called normal grade lead-free fuels, such as Research Octane Number (RON) greater than about 91-92 or antiknock index (AKI) greater than about 85-87, the fuel would be considered octane-rich with slightly higher values for medium and high grade lead-free fuels, respectively. In this context, it will be understood that there is a regional variation in the values of RON, AKI, or other octane or cetane indicia, and the values explicitly discussed in the previous sentence contemplate the U.S. market. However, such values are to be understood as being suitably adjusted to account for such regional variations, and all such values are considered to be within the scope of the present disclosure within their respective region, country, or relevant jurisdictions. As with octane, as the n-hexadecane (n-hexadecane, C) of fuel₁₆H₃₄) Or a component having equivalent ignition delay characteristics, is greater than the concentration of readily available market fuels, then the fuel is considered cetane-rich. For example, if the Cetane Number (CN) of a fuel is greater than about 40-45 (which is a suitable variation for most U.S. markets elsewhere), the fuel will be considered cetane-rich.

Referring first to fig. 1, a vehicle 100 includes a chassis 110 having a plurality of wheels 120. The chassis 110 may be a body frame construction or a one-piece construction, and both configurations are considered to be within the scope of the present disclosure. A passenger compartment 130 is formed inside the chassis 110 and serves as a place where passengers and goods are carried and where a driver can operate the vehicle 100. A guidance device (which may include, among other things, a steering wheel, an accelerator, a brake, etc.) 140 is used in conjunction with the chassis 110 and wheels 120, as well as other systems, to control movement of the vehicle 100. The ICE150 is located in an engine compartment in or on the chassis 110 to provide propulsion power to the vehicle 100, while the controller 170 interacts with the ICE150 to provide instructions for the operation of the latter.

Referring next to FIG. 2, details associated with the structure and operation of the ICE150 and a portion of the controller 170 are shown. The ICE150 includes an engine block 151 having a plurality of cylinders 152, a crankshaft 153 rotatably movable within the block 151, a plurality of cams 154 responsive to movement of the crankshaft 153, a head 155 coupled to the engine block 151 to define a plurality of combustion chambers 156. The head 155 contains inlet valves 157 and exhaust valves 158 (only one of each valve is shown), which in one form may be spring biased to move in response to the crankshaft 153 by corresponding ones of the cams 154 controlled by a chain driven by the crankshaft, a crankshaft-actuated pushrod, or a pneumatic actuator (neither shown). Air inlet 159 and exhaust gas outlet 160 are in selective fluid communication with each of the combustion chambers 156 through fuel injectors 161, while pistons 162 are received in each respective cylinder 152 and coupled to crankshaft 153 through connecting rods 163, such that reciprocating movement of pistons 162 in response to SI or CI combustion occurring within combustion chambers 156 is translated into rotational movement of crankshaft 153 through pivotal movement of connecting rods 163 and crankshaft 153 for subsequent delivery of power to the remainder of the powertrain formed by ICE150, a transmission, an axle, a differential (none shown), and wheels 120. Although the ICE150 is shown without spark ignition devices (e.g., spark plugs) in a manner consistent with various CI-based engine configurations (e.g., RCCI, HCCI, etc.), it should be appreciated that under certain operating loads or conditions, such as low loads, cold starts, and associated warm-up, such spark ignition (possibly in combination with some throttling) may be used to increase the flame propagation combustion rate while maintaining lower cylinder pressures.

In one form, the ICE150 is configured as a Gasoline Compression Ignition (GCI) engine that may be operated with a gasoline-based fuel. In such cases, the disclosed fuel system may be used to achieve COD by operating on a variety of fuels, including market gasoline, gasoline without oxygenates or related anti-knock compounds (also referred to as base gasoline), or one of many types of gasoline with alkyl, aromatic or alcohol. In one non-limiting example, the boiling temperature of such fuels may be in the range of ambient temperature to about 200 ℃. Unlike the SI mode of operation, which injects fuel substantially during the inlet stroke of four-cycle operation, the GCI mode injects fuel substantially during the compression stroke. In one form, the fuel and air are not completely mixed, which allows control of the staging of the combustion process through the injection process. Moreover, the ignition delay allowed by gasoline-based versus diesel-based fuels will allow the partially premixed fuel and air to become more mixed during compression, which in turn will improve combustion. Gasoline-based market fuels that utilize a certain amount of fuel and air premixing help ensure proper fuel-air equivalence ratios for various engine loads and associated fuel injection timing scenarios. Accordingly, when configured as a GCI engine, an ICE150 using a fuel in the gasoline auto-ignition range (where, for example, the RON is greater than about 60 and the CN is less than about 30) may provide a relatively long ignition delay time compared to conventional diesel fuel. This in turn may improve fuel-air mixing and associated engine efficiency, and reduce soot and NOx formation; this latter improvement in turn simplifies the exhaust gas treatment system, as it is now important to oxidize hydrocarbons and carbon monoxide in an oxygen rich environment, rather than trying to control both NOx and soot. Also, when operating as a GCI engine, the ICE150 requires lower fuel injection pressures than diesel-based CI engines.

Further, when configured as a GCI engine, the ICE150 may utilize gasoline-based market fuels that require less processing; in one form, the fuel may be in the form of a gasoline having an intermediate RON of between about 70 and 85. Such octane concentrations may then be adjusted by the OOD or COD via operation of the fuel system 200 as discussed in more detail elsewhere in this disclosure.

Moreover, unlike the HCCI mode of operation, in which fuel and air are fully premixed prior to introduction into the combustion chamber 156, the GCI embodiment of the ICE150 will allow CI operation at higher engine loads and compression ratios without fear of engine knock. Further, by allowing in-cycle control of combustion phasing, an ICE150 configured as a GCI may utilize fuel injection timing to make it easier to control the combustion process than an HCCI configuration, which may not have precise knowledge of the combination of temperature and pressure inside the cylinder.

In another form, the ICE150 is configured as an SI engine that may be operated with a gasoline-based fuel. In this case, the disclosed fuel system may be used to achieve OOD by operating on a variety of fuels, including market gasoline, gasoline without oxygenates or related anti-knock compounds, or gasoline with one of many types of alkyl, aromatics, or alcohols.

The controller 170 is configured to receive data from the sensors S and provide logic-based instructions to various portions of the fuel system 200, which will be discussed in greater detail later. As will be appreciated by those skilled in the art, the controller 170 may be a single unit, as conceptually illustrated in fig. 1 and 2, or one of a set of distributed units throughout the vehicle 100, this latter configuration being as conceptually illustrated in fig. 3. In one configuration, controller 170 may be configured to have a more discrete set of operational capabilities associated with a lesser number of component functions, such as those associated with the operation of fuel system 200 only. In such configurations associated with performing only functions related to the operation of fuel system 200, controller 170 may be configured as an Application Specific Integrated Circuit (ASIC). In another configuration, the controller 170 may have more comprehensive capabilities such that it functions to control a larger number of components (such as the ICE150) in conjunction with or independent of the fuel system 200. In this configuration, the controller 170 may be embodied as one or more Electronic Control Units (ECUs). It will be understood that the ASIC, ECU, and variations thereof are considered to be within the scope of the present disclosure regardless of the configuration and scope of the functions performed by the controller 170.

In one form, the controller 170 is provided with one or more input/output (I/O)170A, a microprocessor or Central Processing Unit (CPU)170B, a Read Only Memory (ROM)170C, a Random Access Memory (RAM)170D, respectively, connected by a bus 170E to provide connectivity to logic circuits for receiving signal-based data and sending commands and related instructions to one or more of the components within the ICE150, one or more of the components within the fuel system 200, and other components within the vehicle 100 responsive to the signal-based instructions. Various algorithms and associated control logic may be stored in the ROM 170C or RAM 170D in a manner known to those skilled in the art. Such control logic may be embodied in pre-programmed algorithms or associated program code that may be operated by controller 170 and then conveyed in its instructions to fuel system 200 via I/O170A. In one form of the I/O170A, signals from various sensors S are exchanged with the controller 170. The sensors may include pressure sensors, temperature sensors, optical sensors, acoustic sensors, infrared sensors, microwave sensors, timers, or other sensors known in the art for receiving one or more parameters associated with the operation of the ICE150, the fuel system 200, and related vehicle components. For example, one or more sensors S may be used to determine whether there is a minimum threshold level of octane-rich fuel component or cetane-rich fuel component at the respective enriched product fuel tanks 250, 260. Although not shown, the controller 170 may be coupled to other operational components of the vehicle 100, including components associated with movement and stability control operations, while additional wiring, such as that associated with a Controller Area Network (CAN) bus (which may cooperate with or otherwise form part of the bus 170E), may also be included where the controller 170 is formed of various distributed units.

Where the controller 170 is configured to provide control of more than just the fuel system 200 (e.g., operation of one or more of the ICEs 150 or other systems within the vehicle 100), other such signals from the additional sensors S may also be provided in signal form to the controller 170 for appropriate processing by its control logic, including those providing combustion data from the ICE150 to control the mixing or related delivery of fuel and air. As such, in a manner consistent with the various modes of operation of the ICE150, the controller 170 may be programmed with actuators for the various components within the ICE150, including the fuel injector actuators 170F, spark plug actuators (also referred to as spark ignition actuators, for SI operating modes) 170G, engine valve controls 170H, and other actuators that may be used to help provide for the introduction of various forms of fuel into the combustion chamber 156, including actuators associated with multiple late injections, stratified mixtures, Low Temperature Combustion (LTC) processes in a manner that promotes smooth operation and low NOx emissions of the ICE150 over substantially its load-speed range. Within this context, the load-speed map of the ICE150 may be used to identify operating regions, such as those used during cold start and ICE150 warm-up, low ICE150 loads, medium ICE150 loads, and high ICE150 loads, where corresponding lower amounts of exhaust gas re-breathing occur by manipulating overlap of the intake valve 157 relative to the exhaust valve 158, possibly in combination with other methods such as Exhaust Gas Recirculation (EGR), to help provide one or more of combustion control, exhaust gas emissions reduction, or other operability adjustments to the ICE 150.

In addition to providing instructions for combustion control, emissions reduction, and the like, the controller 170 interacts with the conduit 210 and various actuators, valves, and related components to control the operation of delivering market fuel from the fuel supply tank 220, the preheater 230, the separation unit 240, the heat exchanger 243, and the enriched product fuel tanks 250, 260 to facilitate achieving the generation of the OOD or COD required to operate the ICE150 for a given set of loads and related operating conditions. In one form of CAN, the controller 170 may manage fuel flow from one or both of the fuel supply tank 220 or the enriched product tanks 250, 260 to the combustion chamber 156 where the two fuels corresponding to OOD or COD are injected separately or by mixing prior to introduction into the combustion chamber at different ratios depending on load, speed, and other optional parameters associated with operation of the ICE 150.

Specifically, the controller 170 is operable to facilitate customizable fuel injection and subsequent combustion strategies for various CI engine configurations. For example, when used in conjunction with a GCI-based engine, controller 170 may direct fuel to be injected in a staged manner late in the compression phase of a four-cycle operation of the engine. In this way, the fuel supply can be considered to have both local stoichiometric and global stratified properties. Notably, by introducing the octane-rich fuel into the combustion chamber 156 relatively late in the compression stroke and taking advantage of the inherent ignition delay of the fuel (which helps promote additional fuel-air mixing), combustion does not begin until after the end of the injection due to the higher volatility and longer ignition delay of the octane-rich fuel (e.g., gasoline) relative to the cetane-rich fuel (e.g., diesel). To achieve a desired degree of stratification, multiple injections may be used. By operating under LTC conditions associated with stratified fuel combustion, GCI engines can have significantly reduced NOx production and soot emissions while achieving diesel-like thermal efficiency. Moreover, such an approach allows the vehicle 100 to use an on-board market fuel that has a lower octane than would otherwise be used. This is beneficial because such fuels require less processing compared to conventional gasoline and diesel fuels; this in turn reduces other undesirable species (e.g., CO)₂) To the oil tank.

Such instructions provided by the controller 170 are particularly beneficial for multi-late injection strategies for fuel delivery in relevant operating modes of the RCCI or ICE150, in addition to GCI engines, as such delivery is optimized when it coincides with various sequences in the compression stroke that may be measured by the sensor S when detecting Crank Angle (CAD) values of the crankshaft 153 to help control when auto-ignition occurs. In this context, the position of the piston 162 within the cylinder 152 is generally described with reference to CAD before or after a Top Dead Center (TDC) position of the piston 162. The controller 170 may also base such delivery strategies on other ICE150 operating parameters, such as the load and engine speed previously mentioned, as well as the number of times such injections are contemplated. For example, CAD corresponds to a power stroke from 0 ° to 180 °, where 0 ° represents TDC and 180 ° represents Bottom Dead Center (BDC). Similarly, CAD ranges from 180 to 360 for the exhaust stroke, which represents TDC. Also, CAD from 360 to 540 represents the intake stroke, with BDC at the latter. Also, CAD represents the compression stroke from 540 ° to 720 °, with TDC in the latter. For example, the controller 170, when used in a 6-cylinder engine, will cause ignition to occur every 120 ° of crankshaft 153 rotation, that is, three firings per rotation of the ICE 150. Thus, when one firing occurs for each of the six cylinders, the crankshaft 153 has rotated twice to traverse 720 of the rotational movement. Likewise, if the ICE150 is configured as a 4-cylinder engine, ignition will occur every 180 of crankshaft 153 rotation. In one form, one of the sensors S may be a crank sensor for monitoring the position or rotational speed of the crankshaft 153. Data acquired from such crank sensors is routed to controller 170 for processing to determine fuel injection timing and other ICE150 parameters, including ignition timing for those instances where a spark ignition device is being used (e.g., cold start and subsequent warm-up). A sensor S, such as a crank sensor, may be used in combination with other sensors S, such as sensors associated with the position of the valves 157, 158, to monitor the relationship between the valves 157, 158 and the piston 162 in an ICE150 configuration with variable valve timing. Such timing is useful in the CI mode of operation of the ICE 50 because it may early close the exhaust valve 158 during the exhaust stroke and early close the intake valve 157 during the intake stroke; such operations performed by the controller 170 may be used to adjust the effective compression ratio of the ICE150 to achieve the desired temperature and pressure associated with CI combustion. Likewise, when SI combustion is desired, the controller 170 may instruct the valves 157, 158 to decrease the compression ratio consistent with SI operation. Likewise, the controller 170 may-depending on the needs of the ICE 150-provide auxiliary sparking for fuel preparation (e.g., generation of free radicals in an air-fuel mixture). The load markings may be provided using sensed inputs (e.g., inputs from various locations within the ICE150 including CAD from the crankshaft 153, and inputs from driver-based inputs such as an accelerator of the guidance device 140). Likewise, in addition to appropriately adjusting the valves 156, 157, balanced fuel delivery from each of the enriched product tanks 250, 260 using pressurization of the pressure provided by one or more fuel pumps 270 may also be achieved by the controller 170, depending on whether the ICE150 is in the CI or SI operating mode.

The controller 170 may be implemented using a model predictive control scheme, such as a Supervised Model Predictive Control (SMPC) scheme or variation thereof, or such as a Multiple Input and Multiple Output (MIMO) protocol, where the inputs include various post-combustion exhaust gas treatment components, sensors S (e.g., exhaust gas temperature sensors, O), as discussed elsewhere in this disclosure₂Sensors, NOx sensors, SOx sensors, etc.), estimated values (as from a look-up table or computed algorithmically), etc. In this manner, an output voltage associated with one or more sensed values from the sensor S is received by the controller 170 and then digitized and compared to predetermined table, map, matrix or algorithm values such that an output indicative of a certain operating condition is generated based on the difference. These outputs may be used to make adjustments in various components within the scope of controller 170, such as the remaining components associated with fuel system 200.

As mentioned above, in one form, the controller 170 may be preloaded with various parameters (e.g., atmospheric pressure, ambient air temperature and flow rate, exhaust gas temperature and flow rate, etc.) into a look-up table, which may be contained in ROM 170C or RAM 170D. In another form, the controller 170 may contain one or more equation or formula-based algorithms that allow the processor 170B to generate appropriate logic-based control signals based on inputs from various sensors, while in yet another form, the controller 170 may contain both look-up tables and algorithmic features to facilitate its monitoring and control functions. Regardless of which of these forms of data and computational interaction are employed, the controller 170-in conjunction with the associated sensors S and associated flow control conduits 210-operates cooperatively such that as the operating load on the ICE150 varies, appropriate adjustments to the market fuel present in the on-board fuel supply tank 220 can be made to provide the amount of octane or cetane enrichment required for such operating load by mixing the on-board market fuel with one or the other of the product fuels from the enriched product fuel tanks 250, 260.

One parameter of the ICE150 that may be pre-loaded into or generated by the controller 170 is Mean Effective Pressure (MEP). In one form, the MEP may be used to correlate ICE150 operating conditions with fuel demand and various forms of multiple late injection strategies previously discussed for various CI engine configurations. MEP, which encompasses variations thereof that Indicate Mean Effective Pressure (IMEP), Brake Mean Effective Pressure (BMEP), or Friction Mean Effective Pressure (FMEP), provides a value of the ability of a particular ICE150 to operate without regard to the number of cylinders 152 or the displacement of the associated ICE 150. Moreover, it provides a measure of the pressure corresponding to the torque produced, so that it can be considered as the average pressure acting on the piston 162 during different portions of its four cycles (intake, compression, ignition and exhaust). In fact, MEP is a better parameter for comparing the engine for design and output than torque, since it is independent of engine speed or magnitude. In addition, MEPs provide a better indicator than other metrics of the engine (e.g., horsepower), since the torque produced is a function of MEP and displacement only, and horsepower is a function of torque and rpm. Thus, for a given displacement, a higher maximum MEP means that more torque is generated, while for a given torque, a higher maximum MEP means that it is achieved from a smaller ICE 150. Likewise, a higher maximum MEP may be associated with higher stresses and temperatures in the ICE150, which in turn provides an indication of the life of the ICE150 or the extent of additional structural reinforcement in the ICE 150. Notably, extensive dynamometer testing, coupled with appropriate analytical predictions, allows MEPs to be well known for modern engine designs. As such, for naturally aspirated (i.e., non-turbocharged) CI engines, MEP values of about 7.0 bar to about 9.0 bar are typical at engine speeds corresponding to maximum torque (about 3000rpm), while MEP values of about 10.0 bar to about 12.0 bar are typical for turbocharged SI engines. For naturally aspirated SI engines, the MEP value is typically about 8.5 bar to about 10.5 bar, while for turbocharged SI engines the MEP value may be between about 12.5 bar to about 17.0 bar.

Likewise, MEP values may be determined for various operating scenarios of the ICE 150. Such operating regimes may include low power or load (including, for example, engine idle conditions) corresponding in one form to an MEP of up to about 1.0 bar, and in another form to an MEP of up to about 2.0 bar. Likewise, such operating schemes may include normal (or intermediate) power or load corresponding to an MEP of between about 2.0 bar and about 5.0 bar in one form, between about 2.0 bar and about 6.0 bar in another form, and between about 2.0 bar and about 7.0 bar in another form. Further, such operating schemes may include high powers or loads corresponding in one form to MEPs of about 7.0 bar and above, in another form to MEPs of about 8.0 bar and above, in another form to MEPs of about 9.0 bar and above, and in another form to MEPs of about 10.0 bar and above.

As will be appreciated, these and other MEP values may be input into a suitably mapped set of parameters, which may be stored in a memory accessible location (such as the previously mentioned look-up tables) such that these values may be used to adjust various ICE150 operating parameters and for the controller 170 when functioning in diagnostic capabilities. In such cases, it may work in conjunction with some of the sensors S, including sensors that may be used to measure the volume of the cylinder 152 (e.g., via crankshaft 153 angle, etc.).

Referring next to FIG. 3, details associated with managing the thermal balance associated with performing on-board COD and OOD operations while avoiding complex system redundancy of the fuel system 200 are illustrated. Notably, by utilizing the existing on-board fuel delivery and ICE150 operating infrastructure, any on-board cooling and heating required to facilitate various adsorption and desorption based regeneration activities may be achieved without the need for additional equipment or reduced efficiency operating modes of the ICE 150. Fuel system 200 includes a network of pipes, tubing, or associated flow passages that make up conduit 210-along with various valves for preferentially permitting or inhibiting the flow of on-board fuel and its fuel byproducts as needed. Fuel supply tank 220 serves as a main tank for storing market fuel (e.g., regular or even low grade gasoline). The preheater 230 is thermally coupled to fuel delivered from the fuel supply tank 220 via the conduit 210 so that if the market fuel to be delivered to the combustion chamber 156 of the ICE150 or the separation unit 240 (one of which is fluidly coupled to the fuel supply tank 220 via the conduit 210) needs to be heated, it can receive thermal energy from the preheater 230, which in one form can be an electric heater, or in another form a heat exchanger.

Notably, the fuel system 200 may operate using residual thermal energy from the vehicle 100, such as residual thermal energy from waste heat of combustion processes occurring within the combustion chambers 156 of the ICE 150. Such use of existing heat may help increase the compactness of the system by reducing component redundancy. In particular, a batch-like processing method may be conducted within the separation unit 240, wherein a pair of chambers 241, 242 are placed in thermal communication with a heat exchanger 243, all within a housing or associated containment structure. Thus, upon receipt of market fuel from fuel supply tank 220 via conduit 210 and optional preheater 230, first chamber 241 is sized and shaped to fluidly receive aromatic (i.e., octane-rich) compounds such that contact of the aromatic compounds on the surfaces of chamber 241 causes the production of octane-rich adsorbates for the OOD, such as by preferential action of suitable functional groups contained within or formed on the surfaces of the adsorbents comprising chamber 241, as will be discussed in greater detail later in this disclosure. The two-chamber configuration of the separation unit 240 is such that when octane rich adsorption occurs in chamber 241, any adsorbent previously saturated in the other chamber 242 is regenerated by means of a heat exchanger 243 by exposing the adsorbate to elevated temperatures (such as exhaust gas from the ICE150 or hot coolant from a radiator-based cooling system, etc.). This addition of latent or waste heat and subsequent vaporization of the octane-rich adsorbate causes the vaporized adsorbate to be desorbed and released, e.g., into the octane-rich product tank 260, for subsequent use in the combustion chamber 156. With the different selection of adsorbents in chambers 241, 242, a hexadecane-rich adsorbate (rather than an octane-rich adsorbate) can be formed in a manner comparable to COD by using a size-selective adsorbent. In one form, such OOD-specific and COD-specific activities may be achieved by a multi-stage configuration of separation units 240 in which sequentially placed units each having one or more of chambers 241, 242, each configured with an affinity-based or size-selective adsorbent, may be arranged. Thus, in one form, by operation of the adsorbent configured to preferentially retain aromatics or related functional group-based fuel components (e.g., oxygenates or double bond-based alkyls), a number of octane-rich portions of the market fuel are formed on the surfaces of the chamber 241, while a number of cetane-rich portions pass through to become a remainder, which can then be routed (as shown) to the cetane-rich product tank 250 or returned (not shown) to the fuel supply tank 220. In this context, the terms "adsorb", "adsorbate", and variants thereof encompass those portions of the vehicle fuel that are retained by surface (rather than by bulk adsorption) to interact with the adsorbent comprising the chambers 241, 242, while the terms "desorb", "desorbate", and variants thereof encompass portions of the adsorbate that are subsequently liberated from the adsorbent as a result of some regeneration action. In one non-limiting form, such desorption may occur by applying a large amount of heat to the chambers 241, 242 sufficient to vaporize the adsorbate. Further, it is understood that adsorption is a physical phenomenon, as opposed to a chemical reaction, but in some cases the term chemisorption may be used. Likewise, in this context, the remainder (also referred to as filtrate) is the portion of the market fuel exposed to the adsorbent in chambers 241, 242 that is not adsorbed, such as by one or both of the functional group (affinity-based) or molecular sieve (size-selective) operations discussed previously.

The two-chamber configuration of the separation unit 240 facilitates batch processing of octane-enriched or cetane-enriched fuels. Specifically, the two chambers 241, 242 may be operated in a parallel manner such that when one chamber is used as an adsorbent to preferentially capture the octane rich adsorbate's membrane, the other chamber may be exposed to latent heat from the operation of the ICE150 to facilitate regeneration of the adsorbent by desorbing the previously collected adsorbate, after which the roles of the two chambers 241, 242 are reversed by manipulation of the controller 170 by a gas gate (not shown) forming part of the conduit 210. In order to have a compact separation unit 240 that does not add too much weight to the vehicle 100, the adsorbent type is selected to give a high surface area to volume ratio by exploring the geometry and structure of the adsorbent particles and adsorbent beds that make up the two chambers 241, 242. In particular, the higher surface area results in a higher adsorption capacity and a smaller separation unit 240 size, which in turn facilitates ease of system integration.

As previously mentioned, various forms of stratified combustion may give rise to LTC's low NO beneficial to the ICE150_XThe type of mode of operation. With respect to using OOD or COD for a CI engine, the fuel may be formed as a mixture of primary fuel (e.g., gasoline or other low cetane variants) and igniter fuel (e.g., diesel or other high cetane variants), with the location, frequency, and timing of introduction of each varying with concepts or configurations (such as those previously discussed). For example, in one concept, a single high octane fuel is introduced by direct injection during the compression stroke. In such cases, the injection of fuel occurs at a relatively retarded time from the conventional diesel injection timing to ensure adequate mixing. Since the overall combustion process is dominated by a reactively controlled LTC, the resulting NOx and soot emissions tend to be very low. In another case, a single igniter fuel is introduced by direct injection during the compression stroke to facilitate cold start and high load operation where the entire combustion process is dominated by diffusion controlled mixing of the fuel at or near piston 162TDC motion. In yet another case, the dual injection scheme introduces the main fuel early in the compression stroke by port fuel injection, so that it is well mixed with the fresh air supply during the intake stroke, after which the igniter fuel is introduced by direct injection asThe manner in which the ignitability is controlled is such that the overall combustion process is dominated by the spatially well mixed high octane fuel after ignition of the high cetane fuel. As with the first case mentioned previously, such operation produces low NOx and soot emissions due at least in part to the overall lean mixture. In yet another case, the main fuel is introduced by direct injection during the compression stroke and the igniter fuel is introduced by direct injection near TDC to achieve ignition control; in this way, a relatively robust mixture is provided through improved thermal or spatial stratification. This in turn leads to low hydrocarbon, NOx and soot formation at least for relatively low engine loads.

In one form, a so-called partial bypass may be used in intermittent situations (such as cold start, or where one of the two high octane or low octane fuel tanks may be empty) so that a fraction of the market fuel from fuel supply tank 220 is provided directly to combustion chamber 156 without entering separation unit 240. This partial bypass, the operation of which may be established by the controller 170, helps facilitate a continuous supply of fuel to the ICE150, and such continuity is particularly useful under the previously mentioned intermittent operating conditions. Specifically, controller 170 may be used to manipulate various fuel delivery parameters, such as coolant temperature, exhaust gas temperature, level of separated fuel, delivery timing, etc. for such transient operating conditions. This helps promote a wider operating range reactivity difference between the high octane fuel component and the high cetane fuel component, particularly in terms of reducing NOx or soot emissions over a much wider range, thereby reducing the likelihood that a soot/NOx tradeoff must be made.

Various fuel injection strategies may be utilized to achieve optimal efficiency, reduced emissions, and improved combustion robustness as compared to conventional diesel-based cycles, which involve the use of EGR and reduced compression ratios. For example, as part of a larger LTC strategy, EGR is used as a means to dilute the mixture and lower the combustion temperature. Likewise, lowering the compression ratio may help reduce engine friction losses, heat losses, and hydrocarbon emissions.

As previously mentioned, in one form, the sorbent for the chambers 241, 242 is configured to be present on the surface of the sorbent material such that it includes one or more functional groups of the affinity-based sorbent. In another form, the adsorbent may separate the adsorbate by its molecular shape such that it includes a size selective sorbent. For example, to target high cetane fuel components, the design will focus on separating straight or lightly branched paraffins (which tend to be associated with high cetane fuels) from aromatics, cyclic paraffins, and high branched paraffins that tend to be present in high octane fuels. In other words, the solid sorbent may function in two mechanisms, where in the first mechanism, the sorbent is selected to have functional groups that attract specific molecules, such as aromatics, cyclics (and oxygenates, if present). Straight and lightly branched molecules (which may include hexadecane) are not adsorbed and pass through the pores of the chambers 241, 242. The second mechanism is based on the difference in molecular size such that linear molecules (e.g., normal alkanes) can pass through a relatively porous material, while other molecules with larger dynamic diameters are hindered from passing through most pores and accumulating in the adsorption-based chambers 241, 242. In this latter mechanism, a packed bed of size selective sorbent is used for COD generation, since linear alkanes with high CN will enter the smaller pores, while other components with larger molecular size will not, thus allowing these other components to exit first as raffinate. In such cases, the preferentially adsorbed linear alkane may then be desorbed in a manner similar to affinity-based sorbents using thermal energy as discussed in this disclosure. Where the market fuel onboard vehicle 100 is gasoline-based, thermal regeneration as may be available through operation of heat exchanger 243 is particularly appropriate because the separated stream of fuel will tend to have relatively high volatility and associated low temperature boiling points. Examples of the first type of sorbent include: activated carbon, silica and alumina-based sorbents, and generally some types of zeolites and functionalized porous materials. Likewise, zeolites, metal-organic frameworks and structured porous materials can be made to function according to a second mechanism. As such, the chambers 241, 242-in addition to having batch processing capability through selective adsorption and desorption activities-may be established in stages (not shown) in the manner previously discussed such that the first stage preferentially provides affinity-based adsorption of aromatics while the second stage functions like a size-selective molecular sieve. In one form, such grading may be performed sequentially in a common or separate housing in a manner suitable for ensuring that relatively small volume packages fit within the vehicle 100 as unobtrusively as possible. Regardless of the configuration, this multistage process allows the first stage to adsorb octane and the second stage to adsorb hexadecane. Thus, while gasoline has relatively few aromatics with a single benzene ring (such as benzene, toluene, and xylene), diesel fuel has larger aromatics in the form of polycyclic (or Polynuclear) Aromatic Hydrocarbons (PAHs), including naphthalene and its derivatives. It is recognized that there are some cetane-rich additives with functional groups, and thus affinity-based sorbents can also be used for these components if there are some such additives. As such-and according to the requirements associated with a particular market of fuel-the sorbents available to chambers 241, 242 may be selected specifically with high affinity for these components, and the order, placement and configuration of each of chambers 241, 242 may be configured with the appropriate sorbents according to the configuration of fuel system 200. Thus, different adsorbents can be used to adsorb low boiling point linear alkanes as a way to produce fuels with different specifications. For example, to adsorb certain aromatic compounds, the adsorbent comprising chambers 241, 242 may be mesoporous (2-50 nm in diameter) activated carbon, which in turn may result in an average recovery of about 80%. Examples of expected adsorption capacities of some of the aromatic components of the activated carbon are listed in table 1.

TABLE 1

Components	mg/g-adsorbent
		Toluene	15
Naphthalene	45
		1-methylnaphthalene	37

Other natural adsorbents (e.g., coconut shells) can also be used to separate the desired components. In another form, the adsorbent beds of chambers 241, 242 may be comprised of more than one adsorbent to preferentially promote adsorption of the desired species. Regardless of the adsorbent bed selection, performance is optimized in terms of various factors, including the capacity and selectivity of the adsorbent, the concentration ratio of the market fuel (which provides a marker for the aromatic fraction), and how quickly regeneration and desorption-based removal are performed.

The selection of the ICE150 and its associated fuel is dependent, at least in part, on the nature of the fuel and the solid sorbent contained within the chambers 241, 242; such properties may include relative fractions in the market fuel, boiling temperature, and sorbent separation mechanisms. For example, the use of affinity-based sorbents can be used to produce OOD adsorbates for low boiling point fuels such as gasoline, while size-selective sorbents can be used to produce COD adsorbates for such low boiling point fuels. In configurations where separation cells 240 are arranged with cells placed in series, each cell having one or more of the chambers 241, 242 with an affinity-based or size-selective adsorbent as previously discussed, it should be understood that the order of such separation may be first and second affinity-based or first and second affinity-based, depending on the need.

Thus, for a compact and cost-effective vehicle propulsion system, a smaller fraction of the fuel associated with the production of the octane-rich fuel component or the cetane-rich fuel component may be routed through a longer path within conduit 210, while a larger remaining or unseparated fraction may be passed through a shorter path. In this way, the length of the flow path defined by the fuel system 200 components not used to perform such fuel enrichment may be kept relatively short, in particular in view of the fact that: the volume of high octane or high cetane fraction fuel components required in an OOD or COD operation is relatively small compared to the remaining fraction of the market fuel supplied to the separation unit 240 or ICE 150. In one form, the amount of time the ICE150 operates at high loads is relatively small compared to the total operating time. As such, a more compact, low cost fuel system 200 may be achieved when the octane-rich stream or the cetane-rich stream is routed through a longer path, which in one form may involve between about 20% to 30% separation of the market fuel as an octane-rich or cetane-rich fuel stream. It is noted that fuel may not be available for all fuel types at all fueling stations for the general purpose of certain engine configurations. For example, naphtha (that is, the light fuel fraction resulting from distillation and boiling that occurs in the gasoline range from about ambient temperature to about 160 ℃) typically has only between about 1% and 10% aromatics. Thus, in the event that additional CN increase is required for a particular COD application, these aromatic components representing smaller fractions may be separated out, such as by using affinity-based sorbents, as a way to ensure lower combustion temperatures and associated lower NOx generation.

Likewise, in one form, the boiling range of the separated fuel stream is within a range compatible with the heat exchange values that may be provided by operation of the ICE 150. Thus, when such streams have relatively high volatility, as is the case when separating gasoline fractions, then the heat obtained from operating the ICE150 on-board is sufficient to regenerate the sorbent. As such, a gasoline-based market fuel using either the GCI or SI operating modes for the ICE150 may be employed, so long as the boiling range of the adsorbate or residue is compatible with the thermal environment generated in the heat exchanger 243.

When using the heat exchanger 243, the controller 170 may instruct to switch between fuel and fresh air flow between the two chambers 241, 242 by one of three different techniques. In a first technique, the sensor S is connected to the outlet of the first chamber 241 such that when the content of aromatics in the inlet and outlet liquid streams as detected by the sensor S are equal (which in turn provides a sign of saturation since no additional aromatics concentration change occurs), the controller 170 switches the delivered market fuel from the fuel supply tank 220 to the second chamber 242 in response to such acquired signal. In a second technique, a timer is connected to the controller 170 to allow it to be turned on and off at intervals (e.g., every 15 minutes), where the intervals depend on the adsorbent size and adsorption rate. In a third technique, the sensors S may be temperature sensors such that once the temperature at the respective chambers 241, 242 no longer increases (which in turn provides an indication of no further heat release due to adsorption), the controller 170 switches the flow of fuel from the first chamber 241 to the second chamber 242.

To regenerate the saturated chambers in chambers 241, 242, a heat source provided by exhaust gas or hot coolant is admitted to heat exchanger 243. Due to the temperature rise, if the drive cycle is required to operate, at least a portion of the adsorbed aromatic compounds on the exposed ones of the chambers 241, 242 are released as vapors for delivery to the combustion chamber 156 or otherwise stored in the low cetane (i.e., high octane) product tank 260, which in one form may be condensed by the air stream, and in another form may be condensed by the market fuel residing within the fuel supply tank 220, such that the market fuel may be used as the condensing medium. Although not shown, the latter form of condensation may be carried out by appropriately routing the vaporized desorbent through a portion of the conduit 210. In one form, any such condensed liquid may be placed in selective (rather than constant) fluid communication with the desorbed vapors, as there may be some modes of operation of the ICE150 that it is desirable to pass desorbed octane or hexadecane directly to the combustion chamber 156 for use (as previously mentioned in connection with certain drive cycles).

With particular reference to the previously mentioned partial bypass, under certain operating conditions (also referred to as first operating conditions) of the ICE150, it may be desirable to use the SI operating mode for reliable operation because, under start-up or other scenarios, there is no exhaust gas or radiator hot fluid available to heat the adsorption cycle, or there is no high cetane fuel or high octane fuel in the enriched product tanks 250, 260. Furthermore, the partial bypass avoids additional undesirable delays associated with sudden driving conditions with respect to speed or load, as well as driving conditions related to weather conditions. Under such partial bypass operating conditions, the controller 170 may direct a fraction of the market fuel from the fuel supply tank 220 to be supplied directly to the combustion chamber 156 without entering the separation unit 240. This fraction may be controlled and manipulated by different methods such as the temperature of the coolant or exhaust gas, the level of the separated fuel, time, or other variables. Two examples are presented to highlight the benefits associated with partial bypass operation.

First, during start-up of the ICE150, when no heat is available to operate the adsorption cycle and no fuel fraction is available, the controller 170 works together so that the fuel stream may come in part from the two enriched product tanks 250, 260 and the main fuel portion from the fuel supply tank 220. If either of the two enriched product tanks 250, 260 is empty at any time (e.g., lack of heating required for desorption or insufficient air cooling, as associated with an unexpected driving cycle condition), the controller 170 may instruct one or more fuel pumps 270 (only one of which is shown) to pressurize the market fuel delivered directly to the combustor 156 from the fuel supply tank 220 to at least partially bypass the separation unit 240 to compensate for the shortage in the cetane enriched product tank 250 or octane enriched product tank 260.

Notably, the fuel system 200 is designed to avoid the use of supplemental equipment, but rather utilizes components that have been operated for other purposes, such as fans (not shown) that move ambient air for cooling during the adsorption step and the fuel pump 270 (although similar equipment may even be reduced, simplified, or eliminated where common rail fuel injection may be used). In one form, the fuel injection pressure generated by fuel system 200 may be up to about 500 bar for gasoline direct injection and up to about 2500 bar for common rail diesel injection, where this higher injection pressure is used to expand the operating zone of diesel-based CI engines because it facilitates premixed CI combustion. In doing so, this latter pressure increase for a diesel fuel based engine may offset the required robustness of the configuration and the reduction in compression ratio and fuel ignition delay. As previously mentioned, the fuel system 200 leverages latent heat associated with general ICE150 operation.

Referring next to fig. 4, an example is provided to demonstrate the applicability of the proposed method and system, with particular emphasis on small adsorbent sizes and fast adsorption rates γ for three different temperatures of 150 ℃, 180 ℃ and 210 ℃ for a 1000cc zeolitic adsorbent sample with a Y-based framework; this size is chosen because it is considered compatible with vehicle-based applications. Specifically, the adsorbent employed was zeolite NaY having a geometric volume of alpha-cages (0.294cc/g) and beta-cages (0.054 cc/g). Table 2 shows this type of adsorption capacity of various aromatic molecules present in commercially available gasoline-based market fuels on an adsorbent.

TABLE 2

Although the process of adsorbing aromatics using Y-based zeolites tends to be relatively slow, there is no need to wait for complete equilibration, as many of the aromatic species contained in the market fuel reach saturation levels more quickly. For example, toluene is adsorbed and reaches equilibrium within 20 minutes, with essentially complete equilibrium occurring after about 1.0 to 1.7 hours. Also, as shown, the adsorption rate γ increases with increasing temperature. This allows for easy estimation of the adsorbate rate within the adsorption cycle. Notably, it has been demonstrated that various enriched fuel components can be produced in a timely manner using adsorption-based devices that can meet the relatively small volume requirements required for placement within a vehicle enclosure.

Referring next to fig. 5, the amount of octane-enriched fuel that can be separated on-board the fuel system 200 using zeolite-based adsorbents in the reactant chambers 241, 242 having the properties listed in table 2, discussed previously, and table 3 below is shown. For example, the vehicle 100 may be configured as a passenger vehicle that consumes on average 6 liters of fuel per 100 kilometers over city and highway distances and operating at an average speed of 70 kilometers per hour; in such cases, the gasoline demand may typically be 4.5 liters/hour.

As another example, the vehicle 100 may be configured as a compact vehicle containing 30% aromatics consumed at a rate of 0.48 liters/hour that consumes 1.6 liters/hour of 95RON gasoline. More specifically, the aromatic compound molecule contained toluene (0.192 liters/hr), xylene (0.192 liters/hr), benzene (0.048 liters/hr) and mesitylene (0.048 liters/hr). The amounts of adsorbate are shown as three conceptual cycle times of 10, 20 and 100 minutes for 1000cc of Y-based zeolite adsorbent. As this fuel stream passes through the adsorbent bed formed on each of the reactant chambers 241, 242, the aromatic molecules are separated and attracted to the adsorbent particles at different rates depending on molecular shape, size, etc.

After only 10 minutes of operation, 6% of the regular gasoline was separated into high octane gasoline with 119 RON. Likewise, after only 20 minutes, 12% of the regular gasoline separates into 119RON gasoline, while full equilibrium is reached after 160 minutes. The results show that adsorption-based OODs can be used for in-vehicle applications in terms of system size and operating time.

TABLE 3

Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it should be noted that various details disclosed in the present disclosure should not be considered as implying that such details relate to elements that are essential components of the various described embodiments, even though specific elements are shown in each figure of the present specification. Further, it will be apparent that modifications and variations are possible without departing from the scope of the disclosure, including but not limited to the embodiments defined in the appended claims. More specifically, although some aspects of the present disclosure are identified as preferred or particularly advantageous, it should be appreciated that the present disclosure is not necessarily limited to these aspects.

It is noted that one or more of the appended claims utilize the term "wherein" as a transitional phrase. For the purpose of defining features discussed in this disclosure, it is noted that this term is introduced in the claims as an open transition phrase that is used to introduce a recitation of a series of characteristics of a structure and that should be interpreted in a manner similar to the more commonly used open predecessor term "comprising".

It is noted that terms like "preferably," "generally," and "typically" are not utilized to limit the scope of the claims or to imply that certain features are critical, essential, or even important to the structure or function of the disclosed structure or function. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the disclosed subject matter. Likewise, it should be noted that the terms "substantially" and "approximately," as well as variations thereof, are used to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. As such, the use of these terms is intended to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

It will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the present specification cover the modifications and variations of each described embodiment provided they come within the scope of the appended claims and their equivalents.