Methods and systems for utilizing plasmas in reactors with transient pressure conditions

Abstract

The present disclosure relates to apparatus, systems, and methods for producing non-thermal plasmas (NTPs) at greater than atmospheric pressure. In some embodiments, an apparatus comprises a first chamber that defines a variable, an actuator, and a plasma generator. The actuator is configured to transiently vary a pressure within the variable volume of the first chamber. The plasma generator is configured to produce plasma within at least one of the variable volume of the first chamber or a volume of a second chamber. The plasma generator is in selective fluid communication with the variable volume of the first chamber.

Description

Agent’s File Ref. EMVL-003 / 01WG 353000-2012METHODS AND SYSTEMS FOR UTILIZING PLASMAS IN REACTORS WITH TRANSIENT PRESSURE CONDITIONSCROSS REFERENCE TO RELATED APPLICATION[00011 This application claims priority to U.S. Provisional Patent Application No. 63 / 713,386, filed October 29, 2024, and titled “METHODS AND SYSTEMS FOR PRODUCING NON-THERMAL PLASMAS AT ELEVATED PRESSURE,” the content of which is incorporated by reference herein in its entirety.GOVERNMENT SUPPORT[0002J This invention was made with government support under Award Number DE- SC0020700 awarded by the Department of Energy. The government has certain rights in the invention.FIELD[0003J One or more embodiments described herein relate to apparatus, systems, and methods for producing non-thermal plasmas (NTPs) at greater than atmospheric pressure.BACKGROUND[0004J Some known techniques apply non-thermal plasmas (NTPs) at ambient (e.g., atmospheric) pressure or below ambient pressure during chemical synthesis. Some known industrial scale implementations of NTPs are used to generate ozone. Known plasma and / or plasma catalysis systems that operate at atmospheric pressure include a packed bed reactor (PBR) and a gliding arc reactor (GAR). In a PBR, gas flow having a pressure at or below ambient flows across a catalyst in a tube. The central shaft of the tube is a high voltage electrode, and an annular ground electrode is disposed outside of and concentric to the tube. An inner surface of the tube includes a dielectric material, and a dielectric barrier discharge (DBD) is formed between the inner conductor (e.g., the shaft) and the outer conductors (e.g., the inner surface of the tube). The field of the DBD is typically modified by the presence of the catalyst (e.g., a dielectric catalyst). The design of the PBR can cause the discharge to remain close to the catalyst surface so that excited species in the gas can interact with the catalyst surface before quenching. In a GAR, a “warm plasma” (e.g., a plasma that is in non-equilibrium326310289 1Agent’s File Ref. EMVL-003 / 01WG 353000-2012 while having significant gas heating) is created between two electrodes as gas flows between these two electrodes. A combination of heat and high-energy electrons activates the gas, and the gas then reacts either in the gas phase or with a downstream catalyst.

[0005] Both PBRs and GARs have significant limitations, particularly at large scales (e.g., in industrial application). For example, because PBRs and GARs operate at ambient pressures, plasma length scales are typically on the order of 1 cm. Therefore, reactor design is significantly constrained to small sizes. Moreover, to achieve suitable residence times, flow rates within PBRs and GARs are also limited. If gas flow rate is increased to achieve higher throughput, conversion rate is significantly reduced because less gas interacts with the plasma. As a result, reactor throughput is low to achieve reasonable conversion efficiency. Scale-up to industrial scale would require large numbers (e.g., hundreds to thousands) of individual reactor units operating in parallel, which can significantly increase complexity and / or capital cost. There is a need, therefore, for systems and methods that produce NTPs at above ambient pressure to facilitate large scale chemical synthesis and / or reaction rate enhancement. f 0006 [ Additionally, in at least some instances, NTPs can be effective at breaking chemical bonds due to target energy deposition of NTPs. In plasma synthesis and / or plasma catalytic synthesis, for example, the chemical bonds of feedstock can be broken by plasma, and when the resulting radicals recombine, those radicals create the target product. This recombination can occur in a gas phase and / or on the surface of a heterogenous catalyst. A challenge with at least some NTP reactors involves separation of the plasma-driven bond-breaking process from the bond-forming process. If these processes are co-located in space and time, the plasma can break apart the bonds in the product species, limiting yield. In some known GARs, spatial separation of plasma and catalyst is accomplished by locating the catalyst downstream of the discharge. In some known PBRs, the plasma occurs in the gas phase while recombination occurs on the surface of the catalyst, which is separated from the high energy electrons of the plasma by a boundary layer. The effectiveness of these GARs and PBRs, however, depends on the lifetime of the intermediate radicals and the timescales of mass transport between the creation location in the plasma and the recombination location. A need exists, therefore, for systems and methods configured to implement a batch process that facilitates temporal separation of the bond-breaking and recombination.326310289 2Agent’s File Ref. EMVL-003 / 01WG 353000-2012BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 shows a block diagram of a transient reactor system, according to an embodiment.

[0008] FIG. 2 shows a block diagram of a compute device included in a transient reactor system, according to an embodiment.

[0009] FIG. 3 shows a graphical representation of plasma discharge energy for an example non-thermal plasma that is subjected to various stationary and transient pressure conditions, according to an embodiment.

[0010] FIG. 4 shows representations of example catalyst geometries for use in a transient reactor system, according to an embodiment.

[0011] FIG. 5 shows a cross-sectional representation of a first example piston-cylinder assembly included in a transient reactor system and having head-mounted electrodes and catalyst, according to an embodiment.

[0012] FIG. 6 shows a cross-sectional representation of a second example piston-cylinder assembly included in a transient reactor system and having head-mounted electrodes and catalyst, according to an embodiment.

[0013] FIG. 7 shows a cross-sectional representation of a third example piston-cylinder assembly included in a transient reactor system and having piston-mounted electrodes and catalyst, according to an embodiment.

[0014] FIG. 8 shows a cross-sectional representation of a fourth example piston-cylinder assembly included in a transient reactor system and having piston-mounted electrodes and catalyst, according to an embodiment.

[0015] FIG. 9 shows a cross-sectional representation of a fifth example piston-cylinder assembly included in a transient reactor system and having a head-mounted electrode and a piston-mounted catalyst, according to an embodiment.

[0016] FIG. 10 shows a cross-sectional representation of a rotary engine included in a transient reactor system and having stator housing mounted electrodes and catalyst, according to an embodiment.

[0017] FIG. 11 shows a schematic representation of a transient reactor system, according to an embodiment.326310289 3Agent’s File Ref. EMVL-003 / 01WG 353000-2012

[0018] FIG. 12 shows a schematic representation of piston-cylinder assemblies having membranes configured to separate a catalyst from oil and / or other lubricants, according to an embodiment.

[0019] FIG. 13 shows a schematic representation of a piston-cylinder assembly that is operably coupled to an external volume, according to an embodiment.

[0020] FIG. 14 shows a schematic representation of a plurality of piston-cylinder assemblies that is operably coupled to an external volume, according to an embodiment.

[0021] FIG. 15 shows a schematic representation of atransient reactor system that includes a compute device, according to an embodiment.

[0022] FIG. 16 shows a schematic representation of a transient reactor system that includes an external volume, according to an embodiment.[0023 j FIG. 17 shows a schematic representation of a transient reactor system that includes a camshaft, according to an embodiment.DETAILED DESCRIPTION

[0024] Non-thermal plasmas (e.g., “NTPs,” non-equilibrium plasmas, cold plasmas, etc.) can be used in, for example, chemical synthesis, reaction rate enhancement, and / or the like. In some instances, NTPs can improve reactions that have high activation energy barriers because the plasma can provide an alternative pathway by which the reaction can proceed. More specifically, an electric field can be applied to an NTP to impart energy that can accelerate electrons (e.g., to a few electronvolts (eV)) to produce high energy electrons. These high energy electrons can collide with heavy particles (e.g., ions, neutrals, cold gas molecules) and transfer energy, exciting internal degrees of freedom (e.g., producing sufficient energy to activate internal motions, such as rotations or vibrations, of the heavy particles) and causing high energy particles as a result. The excited high energy particles can then contribute stored energy to reactions to overcome activation energy barriers. In some instances, overall energy input can be lower when using NTPs as opposed to thermal activation during a reaction. For example, while thermal activation distributes energy over all available modes, NTPs can selectively excite particular modes. To illustrate, dissociation of diatomic nitrogen can involve approximately 9.8eV. Using thermal activation, achieving this energy can in some instances involve temperatures of several thousand Kelvin or more. Conversely an NTP having high- energy electrons can bypass this limitation by directly causing the dissociation. Catalysis can326310289 4Agent’s File Ref. EMVE-003 / 01WG 353000-2012 also be an alternative pathway to splitting stable bonds. Using the above example of diatomic nitrogen, this bond can be split using, for example, iron- and / or ruthenium-based catalysts during the synthesis of ammonia. Combining the benefits of plasma and catalyst can be referred to as plasma catalysis.10 25) At least some systems and methods described herein can support a variety of reactions / chemistries. Examples of plasma-assisted reactions / chemistries include, but are not limited to, hydrocarbon reforming (e.g., steam reforming, dry reforming, and / or partial oxidation), hydrocarbon dehydrogenation and cracking, ammonia synthesis and / or decomposition, nitrogen oxide reduction, nitrogen activation via plasma excitation (enabling formation of nitrogen oxides (NO, NO2, etc.) and / or downstream conversion to nitric acid and / or other nitrogen-containing products), sulfur compound conversion (e.g., H2S decomposition), and / or Fischer-Tropsch-type synthesis from CO and H2.

[0026] Using at least some known techniques, NTPs cannot be efficiently generated at high pressure (e.g., above atmospheric pressure), which can limit plasma chemical synthesis and / or plasma catalysis. For example, using at least some known techniques at pressures higher than atmospheric pressure, voltage sufficient to generate the NTP can be increased (e.g., to prohibitively high levels). Moreover, at higher pressure, the typical length scale of a plasma can be reduced compared to a length scale of a plasma generated at lower pressure. This reduced length scale can result from the reduced electric field (which can be a governing parameter for the discharge formation), which can scale proportionally to the applied voltage and can be inversely proportional to both discharge scale and pressure, as shown below:E _ V kBT N ~ d ~£[O027J Inthe above equation, - is the reduced electric field, V is the applied voltage, d is the discharge length scale, T is gas temperature (e.g., heavy particle temperature), P is gas pressure, and kBis a proportionality constant (e.g., the Boltzmann constant).[0028J Generating NTP at pressures above atmospheric pressure can facilitate, promote, and / or improve yield in at least some reactions. For example, higher pressures can favor equilibrium in at least some reactions. Similarly, in at least some plasma catalysis systems, catalyst adsorption rates can increase with increasing pressure. Higher pressure can also facilitate more frequent collisions and / or faster quenching within reactions, which can improve throughput. While some reactions and / or chemical syntheses can be performed without a326310289 5Agent’s File Ref. EMVL-003 / 01WG 353000-2012 plasma (such as NTP) at a pressure and / or temperature that is typical of a cylinder’s operating condition, such reactions and / or syntheses occurring within a cylinder may have residence times too low to achieve the desired reaction progress. By introducing NTP to the cylinder, equilibrium and / or super equilibrium yields can be produced from the reactions and / or syntheses despite the reduced residence time. As a result, system throughput (e.g., chemical synthesis) can be improved and / or recirculation can be reduced by introducing NTP to incylinder reactions and / or chemical syntheses.[00291 In some instances, in-cylinder plasma catalysis provides benefits even if the plasma is active only during the low-pressure portion of a cycle. As described herein, spatial, and / or temporal separation of plasma and catalytic processes can result in an improved transient reactor system by separating the bond-breaking and bond-forming processes. For example, a transient reactor system described herein can include an engine configured to (1) cause plasma to produce radicals at low pressure and (2) facilitate a compression step to permit the radicals to react at high pressure. This temporal separation prevents the plasma from breaking bonds in the product species, which are formed later in the cycle. This temporal separation further allows plasma to be created during the low-pressure portion of the cycle (when plasma formation is easier) and the synthesis to occur during the high-pressure portion of the cycle (when higher pressure favors product formation). In some implementations, the transient reactor system can stop plasma generation / activation before compression occurs. For example, a transient reactor system can generate plasma at ambient pressure and then perform a compression step (e.g., with or without sustaining the plasma at higher pressure). As a result, the transient reactor system can be configured to, in some implementations, leverage at least one of thermal and / or non-thermal plasma to facilitate reactions.[0030J At least some systems and methods described herein can be used to produce NTPs at pressures that are greater than atmospheric pressure (e.g., at pressures that are greater than 2 bar) and at, for example, low and / or moderate gas temperatures (e.g., at temperatures below 800 K, below 1000 K, below 3000 K, etc.). For example, at least some systems and methods described herein can cause plasma to be produced within a cylinder of an internal combustion engine (ICE). In some instances, at least some of the systems and methods described herein can be used for in-cylinder synthesis of chemicals.[0031 J In at least some systems and methods described herein, NTPs can be produced within a transient reactor. Although an NTP at high pressures cannot typically be sustained for lengthy periods of time, NTPs can be produced at lower pressures and then sustained at high326310289 6Agent’s File Ref. EMVL-003 / 01WG 353000-2012 pressures for shorter periods of time. The transient reactor can include, for example, a rapid compression machine (RCM) configured for single-cycle operation, an internal combustion engine (ICE) configured for multi-cycle operation, and / or the like.[0032 J An NTP can be created in a volume of gas at low (e.g., at or below ambient) pressure by applying, for example, nanosecond repetitively pulsed discharges (NRPDs, also referred to as high voltage nanosecond duration discharges). These NRPDs can be very short duration pulses (e.g., having a pulse full width at half maximum (FWHM) value <100ns) that can reach, for example, a few tens of kilovolts at peak voltage. The high voltage can create fields that can accelerate electrons to energies that are sufficient to cause ionization and / or excite high energy internal degrees of freedom, while the very short duration can limit (1) ohmic heating of the gas and / or (2) transition to a thermal plasma. The pulse repetition frequency (e.g., 1,000 Hz, 10,000 Hz, greater than 10,000 Hz, hundreds of kilohertz, etc., depending on equipment availability and / or desired operating costs) can sustain a background population of longer-lived excited species and free electrons, causing a cumulative effect across many pulses. The residual gas condition (in this case, excited species, ionized species, free electrons, etc., that remain in the chamber at the time of pulsing) can also facilitate later breakdowns at higher pressures.[0033J In some instances, NRPDs can transition from a non-thermal regime to a thermal regime while still maintaining advantages of targeted energy deposition. While some embodiments are described herein in the context of NRPD having non-thermal plasma properties / advantages, in some embodiments, a transient reactor system can exhibit and / or promote at least some similar properties / advantages if the discharge transitions to thermal plasma. At least some systems and methods described herein can therefore leverage at least one of non-thermal plasma and / or thermal plasma, retaining at least some benefits described herein for each. 0034[ Several NRPDs can be applied (e.g., by a plasma generator controlled via a processor that functionally and / or structurally similar to the processor 220 of FIG. 2) within a low-pressure gas to generate a quasi-steady NTP. Compression within the transient reactor can then occur (e.g., based on the cycle of an ICE and / or within a rapid compression machine (RCM) controlled via a processor that functionally and / or structurally similar to the processor 220 of FIG. 2). As the gas is compressed, the NRPDs can continue to be applied. Because of an existing level of ionization that is created at low pressure, the transient reactor can sustain £ the NTP even as the reduced electric field - decreases due to increasing pressure caused by the326310289 7Agent’s File Ref. EMVL-003 / 01WG 353000-2012£ compression. Although - can be reduced to a degree such that ionization is no longer sufficient£ for initiating ignition and / or sustaining indefinite discharge, - can remain high enough during compression to (1) prevent excessive electron attachment and / or (2) continue to accelerate electrons to energies that are suitable for exciting lower energy levels in molecules (rotational, vibrational, and / or electronic degrees of freedom).[0(135] Further reduction of the breakdown voltage can be achieved by introducing species into the chamber that have characteristics that will favor breakdown of the plasma. Such species can include species with low ionization potential (such as alkali element) as well as through the introduction of nanoparticles that facilitate the breakdown. Gases that include molecules and / or atoms that have long decay times can promote restriking of the discharge after the initial pulse / pulses (e.g., at low pressure).

[0036] In some embodiments, NTP can be produced and / or sustained within an internal combustion engine (ICE). The ICE can include, for example, a diesel engine configured to operate at, for example, (1) ambient intake pressure, (2) a compression ratio of 20, and / or (3) a speed of 1800 rpm, such that the diesel engine can compress the gas on a timescale of, for example, 10-20ms. As used herein, an ICE can include (e.g., in addition to an engine that operates on a combustion cycle) a mechanical apparatus and / or reactor configured to facilitate at least one of reciprocating motion, a constant-mass operation, partial oxidation, and / or a reforming reaction.

[0037] In some embodiments, a transient reactor system can be configured to activate (e.g., apply energy to) an NTP intermittently. For example, in at least some instances where an NTP can facilitate a reaction during the compression stroke of the ICE (e.g., and not during the intake stroke, power stroke, and / or exhaust stroke), the transient reactor system can be configured to selectively generate and / or selectively apply an NRPD(s) (e.g., via a plasma generator that is functionally and / or structurally similar to the plasma generator 120 of FIG. 1) to a gas based on engine crank-shaft state (e.g., position), to cause ignition (e.g., plasma activation) of the gas and produce an NTP. More specifically, in some implementations, the transient reactor system can be configured to generate a burst of pulses during a time period after an intake valve of the cylinder closes (e.g., after the cylinder has breathed in reactant gas) and before a pressure within the cylinder exceeds a threshold pressure (e.g., 30 bar, less than 30 bar, or more than 30 bar (e.g., 200 bar, 300 bar, etc.)) where the NTP can no longer be326310289 8Agent’s File Ref. EMVL-003 / 01WG 353000-2012 sustained. By selectively applying NRPD bursts rather than continuously applying the NRPD bursts, wasted energy can be reduced.

[0038] In some instances, to reduce capital equipment cost, power (e.g., pulse bursts) supplied by a single NRPD generator (e.g., a plasma generator) can be delivered to one or more of an engine’s cylinders over the course of an engine cycle. For example, for an ICE that includes a 4-stroke, 4-cylinder (e.g., inline or opposed) engine, a single plasma generator can apply power (e.g., pulse bursts) within the four cylinders to activate NTP during a compression stroke by applying the power within the cylinder from the four cylinders that is undergoing compression. Matching networks can be used for each electrode in the different cylinders to minimize reflection and improve coupling.10039] In some embodiments, the ICE that implements a reactor of the transient reactor system can have, for example, an opposed-piston, free-piston, and / or linear alternator configuration, such that the ICE includes a reciprocating compression chamber. In some implementations, compression can be mechanically driven, and plasma discharge can be synchronized electrically (e.g., while the piston is at or near top dead center (TDC), as described further herein.

[0040] In some embodiments (e.g., as shown in FIG. 17), an external reactor volume (e.g., a reactor chamber) can be operably coupled to a cylinder of the ICE to increase residence time, as described further herein at least in relation to FIGS. 13-14. A valve can be disposed between the external reactor volume and the cylinder and can be configured to controllably cause the external reactor volume to be in selective fluid communication with the internal volume of the cylinder. More specifically, the valve can be controlled (e.g., via a compute device that is functionally and / or structurally similar to the compute device 110 of FIG. 1 and / or the compute device 201 of FIG. 2) to close off the external reactor volume after the compression stroke to hold high-pressure gas for a plurality of cylinder cycles (e.g., during compression strokes of remaining cylinders from the plurality of cylinders). In some implementations, a plurality of external reactor volumes can be coupled to and / or associated with a cylinder. For example, at the top of the cylinder’s compression stroke (e.g., in response to a piston of the cylinder being at (or substantially near (e.g., within 20% stroke length of)) top dead center within the cylinder), the transient reactor system can generate (1) a first signal (e.g., via a compute device that is functionally and / or structurally similar to the compute device 110 of FIG. 1 and / or the compute device 201 of FIG. 2) to cause a first valve to close and (2) a second signal to cause a second valve to close, where the first valve is associated with a first external reactor volume and the326310289 9Agent’s File Ref. EMVL-003 / 01WG 353000-2012 second valve is associated with a second external reactor volume. As a result, high pressure gas and / or NTP can be disposed within at least one external reactor volume from the two external reactor volumes at a given time. In some implementations, the transient reactor system can produce NTP by applying pulse bursts (e.g., NRPD) and / or a suitable energy for plasma activation to the volume of the cylinder. Alternatively or in addition, in some implementations, the transient reactor system can produce NTP by applying pulse bursts (e.g., NRPD) and / or a suitable energy for plasma activation to the external reactor volume(s).[00411 Although at least some examples described herein relate to systems and methods that produce NTP via NRPD, in some embodiments, a transient reactor system can produce NTP via, for example, alternating current dielectric-barrier-discharge (AC-DBD). In some implementations, to produce NTP via NRPD, the transient reactor system can include a pin-to- pin electrode configuration, a pin-to-plate electrode configuration, and / or a dielectric barrierdischarge configuration (e.g., the includes an insulating (dielectric) material between electrodes that facilitate pulse generation).[0042| As described further herein, at least some systems and methods described herein are configured to include and / or operate in conjunction with a catalyst. A catalyst can include, for example, a noble metal (e.g., platinum (Pt), palladium (Pd), and / or etc.), a base metal (e.g., nickel (Ni), iron (Fe), and / or etc.), a perovskite, and / or etc. Within a transient reactor system, a catalyst can be coated on a cylinder wall(s), supported on structured monoliths and / or foams, and / or suspended in the gas phase.[0043 J In some instances, for use in plasma catalysis, a transient reactor system can be configured to include a catalyst that is co-located with (e.g., disposed proximate to) generated NTP to allow short-lived species included in the NTP to reach and interact with the catalyst. This configuration can be functionally and / or structurally similar to a packed-bed reactor used for atmospheric pressure reactors. For plasma catalytic reactions involving interaction of NTP created short-lived species on the surface of a catalyst, the transient reactor can be configured such that the plasma is created close enough to the surface of the catalyst that the excited species lifespan is sufficient for the species to diffuse to the catalyst before quenching. For example, NTPs in mixtures that include nitrogen create large amounts of vibrationally excited N2 molecules with lifespans of hundreds of microseconds. Adsorption of vibrationally excited N2 on, for example, a Ruthenium-based catalyst, can provide a more favorable dissociation path than direct electron-impact, thermal, or catalytic dissociation of ground-state N2.326310289 10Agent’s File Ref. EMVL-003 / 01WG 353000-2012

[0044] Alternatively, in some instances, a synthesis reaction can involve a metastable species that is generated within the NTP. For example, a synthesis reaction can involve electron impact dissociation of oxygen to produce oxygen radicals. Based on the lifespan of the metastable species (e.g., given sufficiently long lifespan), the metastable species can then interact with a catalyst that is spatially separated from the NTP (e.g., that is not co-located with the NTP). For example, in some implementations, NTP can be included in a cylinder of an ICE and the catalyst can be included in an external reactor volume (and / or vice versa).[00451 In some embodiments, plasma within a reactor (e.g., a reciprocating reactor) can be generated and / or sustained by a dielectric barrier discharge (DBD) device, as described herein. Alternatively or in addition, in some embodiments, the plasma within the reactor can be generated and / or sustained using microwave energy. This microwave energy can be in the frequency range of, for example, 0.915 GHz to 2.45 GHz, although other industrial, scientific, and medical (ISM) bands can also be employed. Microwave power can range from 10 watts to several kilowatts per cylinder, depending on the reactor volume, desired electron density, and / or duty cycle.

[0046] In some embodiments, microwave energy can be applied during the compression stroke of the cylinder, in either one pulse or in a series of pulses (with duty cycles between 1% and 50%), with pulse duration ranging from 1 microsecond (ps) to 1 millisecond (ms), synchronized with piston motion. The transient reactor system can initiate microwave power just before or early in the compression stroke, with the pulse duration extending through all or part of the compression stroke.

[0047] Microwave energy can be directed into the cylinder through a waveguide, coaxial probe, and / or dielectric window, integrated into the cylinder head and / or wall. The cylinder itself can serve as a variable resonant cavity (since cavity height decreases during compression). In some embodiments, the cylinder dimensions and / or inlet / outlet geometries are sized / configured based on a cutoff condition, such that the open cylinder volume does not support propagation of a micro wave frequency.

[0048] To facilitate field penetration and effective coupling at top dead center, a structure(s) can be included within the cylinder volume (such as, for example, a coaxial insert to implement a geometry similar and / or analogous to a coaxial transmission line, which does not, in at least some instances, exhibit a cutoff frequency (or does not exhibit a significant / 326310289 11Agent’s File Ref. EMVL-003 / 01WG 353000-2012 consequential cutoff frequency)). This structure(s) can enable efficient microwave coupling even for geometries that would otherwise block wave propagation.

[0049] In at least some instances, the presence of dielectric materials, including catalyst and / or catalyst supports, such as alumina, silica, cordierite, and / or metal oxides, significantly affects microwave propagation and field distribution. These materials alter the effective cutoff frequency and impedance matching of the cavity and can help focus and / or localize an electric field, enabling localized plasma generation near catalyst surfaces. This effect can enhance reaction rates through plasma-catalyst synergy, as reactive species are generated at and / or near active sites. The dielectric constant and geometry of catalyst inserts can be tuned to control field strength, resonance conditions, and / or plasma uniformity.10050) In some implementations, a microwave generator (from a plurality of microwave generators) can be disposed at, operably coupled to, and / or associated with each cylinder of a transient reactor system. The low cost / mass production of compact microwave generators, especially those operating at, for example, 2.45 GHz, can facilitate this approach. Alternatively, a single generator can be used to distribute microwave energy across multiple cylinders.

[0051] FIG. 1 shows a system block diagram of a transient reactor system 100, according to an embodiment. The transient reactor system 100 includes a compute device 110, a plasma generator 120, an internal combustion engine (ICE) 150, and a network Nl. Optionally, the transient reactor system 100 can include a valve 130 and an external reaction chamber 140. The ICE 150 includes a cylinder 152, an intake valve 154, apressure sensor 156 (e.g., a pressure transducer), apiston 158, and a crankshaft position sensor 160. In some embodiments, although not shown FIG. 1, the internal combust engine can include a rotary engine, as described further herein at least in relation to FIG. 10. Connection lines with arrows depicted in FIG. 1 can represent control signals, and connection lines without arrows can represent operable connections (e.g., physical connections, functional connections, etc.). The transient reactor system 100 can include alternative configurations, and various steps and / or functions of the processes described below can be shared among various devices of the transient reactor system 100 (e.g., a plurality of compute devices that includes the compute device 110).

[0052] In some embodiments, the compute device 110 can include any suitable hardwarebased computing devices and / or multimedia devices, such as, for example, a server, a desktop compute device, a smartphone, a tablet, a wearable device, a laptop, and / or the like. In some implementations, the compute device 110 can include an engine control unit (ECU). This ECU326310289 12Agent’s File Ref. EMVL-003 / 01WG 353000-2012 can differ from some known (e.g., commercially available) ECU in at least some aspects. For example, as described further at least in relation to FIG. 11, this ECU can include modified software that is configured to receive a crankshaft encoder signal and / or an in-cylinder pressure transducer signal and control a plasma discharge unit based on the signal(s). In some implementations, the compute device 110 can be implemented at an edge (e.g., with respect to the network Nl) node or other remote (e.g., with respect to the network Nl) computing facility and / or device. In some implementations, the compute device 110 can be included in a data center or other control facility and / or device configured to run and / or execute a distributed computing system and can communicate with other compute devices. The compute device 110 can be functionally and / or structurally similar to the compute device 201 of FIG. 2, described herein.

[0053] The plasma generator 120 can be coupled to the internal combustion engine 150 (e.g., via the cylinder 152 and / or the piston 158) as described further herein at least in relation to FIGS. 5-9. The plasma generator 120 can be configured to generate a non-thermal plasma (NTP). For example, the plasma generator can be configured to apply an electric field (or some other energy) to a gas to cause the gas to undergo a state transition to produce the NTP. In some implementations, the plasma generator 120 can include a circuit that is configured to generate a nanosecond repetitively pulsed discharge (NRPD) and apply the NRPD to the gas. In some implementations, the plasma generator 120 can include a dielectric barrier discharge (DBD) device that can be configured to cause alternating current (AC) to be supplied to electrodes of the DBD device to generate an electrical discharge and produce the NTP. In some implementations, as described further herein, the plasma generator can be configured to apply an electrical discharge within at least one of a volume of the external reaction chamber 140 and / or a volume of the cylinder 152. The compute device 110 can cause a signal to be sent (e.g., via the network Nl) to the plasma generator 120 to cause the plasma generator 120 to produce the electrical discharge within the cylinder 152 while the piston 158 is undergoing a compression stroke within the piston 158. Alternatively or in addition, the compute device 110 can cause a signal to be sent to the plasma generator 120 to cause the plasma generator 120 to produce the electrical discharge within the external reaction chamber 140 while gas that is suitable for NTP generation is disposed within the optional external reaction chamber 140.

[0054] To produce NTP within a volume of the cylinder 152, the compute device 110 can be configured to cause the plasma generator 120 to apply an electric field within the cylinder 152 in response to the intake valve 154 closing before a compression stroke and / or based on326310289 13Agent’s File Ref. EMVL-003 / 01WG 353000-2012 an angular (rotational) position of a crankshaft that indicates that the piston 158 is bottom dead center within the cylinder 152 and / or has commenced (or will commence) a compression stroke. The crankshaft can be included in the ICE 150, and the crankshaft position can be measured by the crankshaft position sensor 160. The compute device 110 can cause the plasma generator 120 to continue to apply the electric field until the pressure sensor 156 indicates that pressure within the cylinder 152 is higher than a predetermined pressure threshold (e.g., a maximum pressure threshold that can sustain NTP).[0055| The plasma generator 120 can generate plasma through nanosecond-pulsed high- voltage discharges, capacitor discharge systems and / or radiofrequency and / or microwave excitation, or any combination thereof, as described further herein. For nanosecond-pulsed high-voltage discharges, operating parameters of the plasma generator 120 can include, for example, voltages of 5-30 kV, pulse durations of 1-500 ns, and / or repetition rates of 1-100 kHz, each of which can be tunable based on pressure and / or chemistry.

[0056] In some implementations, the compute device 110 can be further configured to cause the valve 130 to transition from an open configuration to a closed configuration when the piston 158 has completed a compression stroke (e.g., when the piston 158 is at least substantially at top dead center within the cylinder 152, as measured by the crankshaft position sensor 160) to cause compressed gas and / or NTP to flow from the cylinder 152 to the external reaction chamber 140.

[0057] In some embodiments, the transient reactor system 100 can include additional sensors not shown in FIG. 1. For example, in some embodiments, the transient reactor system 100 can include at least one of a gas composition detector, a temperature transducer, an electrical discharge monitor, a vibration sensor, and / or etc. These sensors can be used by the transient reactor system 100 to facilitate closed-loop control to, for example, optimize (or improve) plasma discharge timing, detect fouling, and / or trigger self-cleaning and / or modeswitching protocols.

[0058] The compute device 110 can be networked and / or communicatively coupled to other components shown in FIG. 1, via the network Nl, using wired connections and / or wireless connections. The network Nl can include various configurations and protocols, including, for example, short range communication protocols, Bluetooth®, Bluetooth® LE, the Internet, World Wide Web, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more326310289 14Agent’s File Ref. EMVL-003 / 01WG 353000-2012 companies, Ethernet, WiFi® and / or Hypertext Transfer Protocol (HTTP), cellular data networks, satellite networks, free space optical networks and / or various combinations of the foregoing. Such communication can be facilitated by any device capable of transmitting data to and from other compute devices, such as a modem(s) and / or a wireless interface(s).10059 J In some implementations, although not shown in FIG. 1 , the transient reactor system 100 can include multiple compute devices 110. For example, in some implementations, the transient reactor system 100 can include a plurality of compute devices 110 (e.g., multiple controllers).

[0060] While some embodiments described herein (e.g., as shown in FIG. 15) include a compute device (e.g., an ECU) configured to trigger a plasma generator and / or a compression device, in other embodiments, a transient reactor can include mechanical triggers (e.g., and exclude a compute device). For example, in some embodiments, as shown in FIG. 17, the transient reactor can include a mechanical actuator (e.g., a cam on the camshaft of the ICE). The mechanical actuator can be configured to trigger pulse generation. More specifically, in some implementations, the transient reactor can include a trigger configured to generate a continuous trigger pulse at a predetermined frequency (e.g., that is determined based on the frequency of a cylinder cycle and / or that is predetermined and remains fixed independent of RPM). A cam coupled to the ICE (e.g., a cam mechanically linked to the camshaft) can be configured to close a circuit to direct the trigger pulse to a pulse generator for the duration of the cylinder cycle that activated plasma is desired. Moreover, in some embodiments, the transient reactor can include a mechanical actuator (e.g., a cam on the camshaft of the ICE) that is configured to trigger a valve(s) to an external volume to permit flow of gas (e.g., compressed gas) to and / or from a cylinder volume, as shown in FIG. 16 and described further herein.[00611 FIG. 2 shows a system block diagram of a compute device 201 included in a transient reactor system, according to an embodiment. The compute device 201 can be a hardware-based computing device, a multimedia device, or a cloud-based device such as, for example, a computer device, an electronic control unit (ECU), an electronic control module (ECM), an embedded controller, a server, a desktop compute device, a laptop, a smartphone, a tablet, a wearable device, a remote computing infrastructure, and / or the like. The compute device 201 includes a memory 210, a processor 220, and a network interface 230 operably coupled to a network N2.326310289 15Agent’s File Ref. EMVE-003 / 01WG 353000-2012

[0062] The processor 220 can be, for example, a hardware-based integrated circuit (IC), or any other suitable processing device configured to run and / or execute a set of instructions or code (e.g., stored in memory 210, described herein). For example, the processor 220 can be a general-purpose processor, a central processing unit (CPU), an accelerated processing unit (APU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic array (PLA), a complex programmable logic device (CPLD), a graphics processing unit (GPU), a programmable logic controller (PUC), a remote cluster of one or more processors associated with a cloud-based computing infrastructure, alone or in combination of the above, and / or the like. The processor 220 is operatively coupled to the memory 210 (described herein). In some embodiments, for example, the processor 220 can be coupled to the memory 210 through a system bus (for example, address bus, data bus, and / or control bus).

[0063] The memory 210 can be, for example, a random -access memory (RAM), a memory buffer, a hard drive, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), and / or the like. The memory 210 can store, for example, one or more software modules and / or code that can include instructions to cause the processor 220 to perform one or more processes, functions, and / or the like. In some implementations, the memory 210 can be a portable memory (e.g., a flash drive, a portable hard disk, and / or the like) that can be operatively coupled to the processor 220. In some instances, the memory can be remotely operatively coupled with the compute device 201, for example, via the network interface 230 and the network N2. For example, a remote database server can be operatively coupled to the compute device 201.

[0064] The memory 210 can store various instructions associated with processes, algorithms, and / or data, as described herein. The memory 210 can further include any non- transitory computer-readable storage medium for storing data and / or software that is executable by the processor 220, and / or any other medium which may be used to store information that may be accessed by the processor 220 to control the operation of the compute device 201. For example, the memory 210 can store machine-readable code that causes the processor 220 to receive measurement signals from a sensor(s) (e.g., a crankshaft position sensor, a cylinder pressure sensor, etc.) that is operably coupled to the compute device 201 via the network N2, as described further herein. The memory 210 can further store machine-readable code that implements a plasma generator control application 212, which can be configured to cause the processor 220 to generate control signals to manipulate (e.g., via the network N2) a plasma326310289 16Agent’s File Ref. EMVL-003 / 01WG 353000-2012 generator. Additionally, the memory 210 can store machine-readable code that implements an external volume valve control application 214, which can cause the processor 220 to generate a control signal to manipulate (e.g., via the network N2) a valve(s) between a cylinder and an external reaction volume, as described herein.[0065 J The network interface 230 can be configured to connect to the network N2, which can include wired connections and / or wireless connections associated with various configurations and communication protocols, including, for example, short range communication protocols, Bluetooth®, Bluetooth® LE, the Internet, World Wide Web, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more companies, Ethernet, WiFi® and / or Hypertext Transfer Protocol (HTTP), cellular data networks, satellite networks, Control Area Network (CAN), Local Interconnect Network (LIN), free space optical networks and / or various combinations of the foregoing. Such communication can be facilitated by any device capable of transmitting data to and from other compute devices, such as a modem(s) and / or a wireless interface(s).[0066J In some instances, the compute device 201 can further include a display, an input device, and / or an output interface (not shown in FIG. 2). The display can be any display device by which the compute device 201 can output and / or display data (e.g., via a user interface). The input device can include a mouse, keyboard, touch screen, voice interface, and / or any other hand-held controller or device or interface via which a user may interact with the compute device 201. The output interface can include a bus, port, and / or other interfaces by which the compute device 201 may connect to and / or output data to other devices and / or peripherals. Alternatively or in addition, the compute device 201 can cause display of data and / or receive data via another compute that includes a display and / or input device.[0067J FIG. 3 illustrates an example of plasma discharge energy as a function of pressure, according to an embodiment. The dashed line (and triangle data points) represents plasma discharge energy for an NTP that is subjected to stationary (e.g., constant, prolonged, etc.) pressure. The solid line (and circle data points) represents plasma discharge energy for an NTP that is subjected to transient pressure as a result of momentary compression within a cylinder. The example gas illustrated in FIG. 3 has a starting temperature of approximately 200-300 °C. As shown by the dashed line in FIG. 3, increasing stationary (e.g., non-transient, non- momentary, etc.) pressure beyond approximately 4 bar causes the plasma energy of the NTP to decrease at a high rate, indicating that the NTP is no longer ignited (e.g., at this point,326310289 17Agent’s File Ref. EMVL-003 / 01WG 353000-2012 deposited energy (e.g., from applied NRPDs) within the system is in parasitic resistance). Conversely, as shown by the solid line in FIG. 3, when an NTP within a cylinder is subject to momentary pressure caused by a compression stroke, the NTP is sustained for pressures beyond 4 bar (e.g., 10-20 bar). As a result, the example NTP represented by the solid line in FIG. 3 undergoes a delayed plasma transition to a non-plasma gas state.

[0068] FIG. 4 shows representations of example catalyst geometries for use in a transient reactor system, according to an embodiment. Some known catalysts can have a packed powder format and / or a pellet format (e.g., l-3mm in size). Such known catalysts of this type(s), however, can result in void spaces that (1) can be randomly distributed and / or (2) can vary depending on how the catalyst is packed within a cylinder. An improved catalyst (e.g., for use in at least some systems described herein (e.g., the transient reactor system 100 of FIG. 1)) can include catalyst support material, a polymeric binder (and / or the like), and / or a crosslinker (examples of which are shown in FIG. 4). Using, for example, three-dimensional (3D) printing techniques, a catalyst having a predefined geometry can be produced from the catalyst support material, polymeric binder, and / or crosslinker. This produced catalyst can facilitate optimized (or improved) catalyst packing and / or minimized (or reduced) void space.[0069} More specifically, as shown in FIG. 4, the catalyst support material (e.g., activated carbon, silicon dioxide (SiCh), aluminum oxide (AI2O3), titanium dioxide (TiCh), ceric oxide (CeCh), any of the foregoing including a promoter and / or dopant, and / or the like) can be combined with a polymeric binder (e.g., and / or any other binder suitable for facilitating 3D printing) and / or a crosslinker (e.g., a ceramic crosslinker, calcium oxide (CaO), and / or any other material suitable for improving temperature stability) to create a mixture (e.g., a filament, paste, etc.). This mixture can then be printed into the desired (e.g., predetermined) shape and heat treated (e.g., calcined) to remove the binder, crosslinker, and / or any other additive, producing a catalyst support having the predetermined shape and including the catalyst support material (and excluding (or substantially excluding) the binder, crosslinker, etc.). The catalyst support can then be impregnated with a catalyst (e.g., an active metal and / or other promotor(s)). In some instances, computational methods (including computation fluid dynamics, kinetic models, and / or plasma models) can be employed to determine a shape of a catalyst- impregnated support for a given gas mixture, desired chemistry, and / or desired plasma characteristic.

[0070] In some implementations, a catalyst can be modified to achieve a higher loading while maintaining a sufficiently small particle size. Such modifications can include, for326310289 18Agent’s File Ref. EMVL-003 / 01WO 353000-2012 example, surface modification (e.g., increasing surface area, modifying a texture to isolate individual particles, etc.) using plasma etching and / or chemical etching techniques. In some implementations, particle size of a catalyst can be maintained (e.g., below a threshold size), and sintering of the catalyst and / or Oswald ripening can be reduced or prevented by adding a stabilizer(s) and / or dopant(s) to the support material. These additives can increase the binding strength of the catalyst to a support material, reducing the occurrence of agglomeration. In some implementations, to resist poisoning by COx, H2O, and / or O2, active materials (e.g., for COx and / or H2O, zeolites, metal-organic frameworks (MOFs), etc.; for O2, Ceria, etc.) can be added to the catalyst formula. These active materials can selectively adsorb poison at high pressure (e.g., during compression), preventing the poisons from deactivating the catalyst under reaction conditions. The poisons can then be removed during expansion and / or by implementing a regeneration cycle.[00711 In some implementations, the regeneration cycle can be initiated by a controller (e.g., similar to a compute device described herein) based on sensor feedback that indicates at least one of performance degradation, fouling, or deviation from a predetermined operating condition (e.g., in a reactor volume / chamber, described further herein). In some implementations, a regeneration cycle can include introduction of a gas (e.g., an oxidizing or reducing gas) that is different than the reactant gas into the chamber and applying a plasma and / or microwave discharge to remove accumulated carbonaceous deposits, sulfur-containing deposits, and / or other compounds from internal surfaces and / or catalyst structures.[00721 In some implementations, a catalyst support can include an insulating material(s). Since in-cylinder temperature distribution can be anisotropic, large temperature gradients can exist within the cylinder. To reduce the magnitude of these gradients, a supported catalyst can be coated in a metal foam. The metal foam can act as a heat sink to reduce hotspots and / or improve conduction. Metal foam can also act as a mechanical support and / or can be machined into any custom geometry.

[0073] The catalyst used can be tailored for a transient plasma-catalysis application. For example, a catalyst with a dielectric support material such as alumina (and / or the like) can be used to provide the dielectric required for a dielectric breakdown. This catalyst configuration can result in a non-thermal plasma distributed over a large volume in close proximity to the catalyst surface and facilitate short-lived plasma species interaction with the surface of the catalyst.326310289 19Agent’s File Ref. EMVL-003 / 01WO 353000-2012

[0074] Catalyst particle size and shape can be chosen to enhance or reduce electric field. Catalyst pellets that are manufactured to have many sharp edges in the macroscale (e.g., cylindrical, or star-shaped extrudates) with significant protrusion can enhance local electric fields providing a preferential location for the discharge to form. This configuration can be advantageous for spark-type discharges. Alternately, smoother catalyst pellets (e.g., that are spherical in shape) can prohibit spark formation and are more likely to lead to a uniform, distributed discharge as may be desired for a DBD-type discharge. The packing of the catalyst can also impact both the plasma regime formation and volume. For example, larger particles can cause many macroscopic voids (e.g., spaces between the particles, as opposed to a microscopic void within a particle), while smaller particles can pack more closely and create smaller macroscopic voids. The plasma formation is sensitive to this void size, with an optimal size dependent on the operating pressure according to Paschen’s Law. For a DBD-style discharge with co-located plasma and catalyst, the packing of the catalyst can be designed to achieve a Paschen-minimum to aid discharge formation. Alternately or in addition, an optimal spacing can be configured such that E / N activates a desired excitation mechanism; smaller spacing for higher E / N targeting electronic excitation and larger spacing for lower E / N targeting vibrational excitation. Large spacing between dielectric particles can also allow sparks to traverse the space between particles more effectively if a nanosecond spark in close proximity to the catalyst is desired.

[0075] The catalyst should be tailored for transient operation since the plasma-catalytic reactor is inherently a transient system. For example, the pressure swing might allow use of catalysts with stronger binding energy than is normally feasible for steady state operation as desorption will be aided by the pressure reduction portion of the cycle. A catalyst might be chosen that can tightly bind to plasma-created meta-stables during the low-pressure part of the cycle and maintain these through to the high-pressure portion. For example, for ammonia synthesis, free atomic nitrogen is relatively short lived. A catalyst may be chosen that tightly adsorbs free atomic nitrogen produced during the discharge and prevents this from reacting with other free nitrogen molecules in the gas phase, keeping it present until the high-pressure portion of the cycle allows for reaction with hydrogen on the surface of the catalyst.

[0076] The catalyst can be designed to aid in heat transfer within the reactor. Nanosecond sparks can produce relatively high temperatures in the plasma channel core even without transitioning to a thermal plasma. It can be desirable to maintain this high temperature in the gas phase to aid gas-phase reactions, in which case an insulating catalyst support material can326310289 20Agent’s File Ref. EMVL-003 / 01WG 353000-2012 be chosen. Conversely, the discharge can be used to help maintain a homogenous catalyst temperature, in which case a catalyst with a high thermal conductivity can be used to distribute the heat throughout the reactor volume.

[0077] FIG. 5 shows a cross-sectional representation of a first example piston-cylinder assembly 500 included in a transient reactor system and having head-mounted electrodes and catalyst, according to an embodiment. More specifically, FIG. 5(a) shows the piston-cylinder assembly 500 during an intake stroke of the piston, where the piston can be disposed at a lower position within the cylinder, the intake valve(s) can be opened, and the exhaust valve(s) can be closed. FIG. 5(b) shows the piston-cylinder assembly 500 at (or substantially near) an end of compression stroke, where the piston can be disposed at (or substantially near) top dead center (TDC) within the cylinder and both the intake valve(s) and the exhaust valve(s) can be closed.]0078] As shown in FIG. 5, an outer surface of a head-mounted center electrode (either smooth or rough) and an inner surface of an outer electrode can define annular volume that is in fluid communication with an interior volume of the cylinder. Catalyst (e.g., that is functionally and / or structurally similar to the catalyst described at least in relation to FIG. 4) can be disposed within the annular volume. The ratio between the diameter of the center and outer electrodes can be, for example, 0.6-0.7, to promote more uniform and / or homogeneous NTP discharges across the lengths of the center and outer electrodes. As shown in FIG. 5(b), with both the intake valve(s) and exhaust valve(s) closed, compressed gas can enter the annular volume (e.g., before the piston is at TDC, while the piston is at TDC, and / or after the piston descend from TDC), and the center and / or outer electrodes can be triggered (e.g., via a compute device that is functionally and / or structurally similar to the compute device 110 of FIG. 1) can produce NTP.|0f)79] In some implementations, the piston-cylinder assembly 500 can be configured to have a long stroke (e.g., where the stroke length of the piston is larger (e.g., 100% larger, 200% larger, etc.) than the bore diameter of the cylinder). This long stroke configuration can reduce the portion of compressed gas that is disposed within a gap between the piston and cylinder head and that does not enter the annular volume defined by the center and outer electrodes while the piston is disposed at or near TDC. This portion of compressed gas can be excluded from a reaction (or produce a lower yield as a result of a reaction) by not being exposed to the catalyst and / or generated NTP within the annular volume. Therefore, by configuring the pistoncylinder assembly 500 to have a long stroke, the amount of compressed gas that can interact with the catalyst and / or NTP within the annular volume can be increased. The long stroke326310289 21Agent’s File Ref. EMVL-003 / 01WG 353000-2012 configuration (e.g., as a result of the narrower bore diameter relative to the piston stroke length) can further reduce the distance between the center and outer electrodes, which can result in a shortened discharge distance between the center and outer electrodes. This shortened discharge distance can improve NTP generation at the elevated pressure conditions that are caused by the piston being at TDC. The piston-cylinder assembly 500 can be included in, for example, a four- stroke engine as a result of the intake and exhaust valve disposed at an upper portion of the cylinder (e.g., the cylinder head).[0080| FIG. 6 shows a representation of a second example piston-cylinder assembly 600 included in a transient reactor system and having head-mounted electrodes and catalyst, according to an embodiment. More specifically, FIG. 6(a) shows the piston-cylinder assembly 600 during an intake stroke of the piston, where the piston can be disposed at a lower position within the cylinder, the intake valve(s) can be open, and the exhaust valve(s) can be closed. FIG. 6(b) shows the piston-cylinder assembly 600 at (or substantially near) an end of compression stroke, where the piston can be disposed at (or substantially near) top dead center (TDC) within the cylinder and both the intake valve(s) and the exhaust valve(s) can be closed.|0081 | The piston-cylinder assembly 600 can be functionally similar to the piston-cylinder assembly 500 of FIG. 5. Unlike the piston-cylinder assembly 500, however, within the pistoncylinder assembly 600, a high voltage electrode can be coupled to an inside surface of the cylinder head, a ground electrode can be mounted below and a distance away from the high voltage electrode, and catalyst can be disposed between the high voltage electrode and the ground electrode. The ground electrode can define at least one hole, be perforated, and / or be otherwise configured to permit compressed gas from an internal volume of the cylinder to the catalyst disposed between the ground and high voltage electrodes. The ground and high voltage electrodes can define two planar geometries (e.g., two parallel discs), and in some implementations, can be separated by an insulating electric barrier (e.g., an insulating dielectric barrier). As a result of the insulating electric barrier, the electrodes defining the planar geometry can produce a dielectric barrier discharge having a substantially uniform field. To reduce the discharge distance (such that the dielectric barrier discharge can be produced while the piston is at or near TDC), the piston-cylinder assembly 600 can have a short-stroke design (e.g., where the stroke length is shorter than the bore size (e.g., the diameter) of the cylinder. As a result of the locations of the intake and exhaust valves, the piston-cylinder assembly 600 can be included in, for example, a two-stroke engine.326310289 22Agent’s File Ref. EMVL-003 / 01WG 353000-2012

[0082] FIG. 7 shows a representation of a third example piston-cylinder assembly 700 included in a transient reactor system and having piston-mounted electrodes and catalyst, according to an embodiment. More specifically, FIG. 7(a) shows the piston-cylinder assembly 700 during an intake stroke of the piston, where the piston can be disposed at a lower position within the cylinder, the intake valve(s) can be open, and the exhaust valve(s) can be closed. FIG. 7(b) shows the piston-cylinder assembly 700 at (or substantially near) an end of compression stroke, where the piston can be disposed at (or substantially near) top dead center (TDC) within the cylinder and both the intake valve(s) and the exhaust valve(s) can be closed.

[0083] As shown in FIG. 7, the catalyst, high voltage electrode, ground electrode, and catalyst can be disposed on the piston crown (e.g., an upper surface of the piston). The cylinder head can include a high voltage trigger (e.g., a switch), and the high voltage electrode can electrically couple to the high voltage trigger to energize the high voltage electrode, causing NTP to be produced between the high voltage and ground electrodes. Although not shown FIG. 7, a sliding contact can be disposed between the high voltage trigger and the high voltage electrode. To reduce friction between components and resulting wear, the sliding contact can include an electrical brush. The sliding contact can be configured to cause discharge to be produced before the piston reaches TDC and / or after the piston descends from TDC. As a result, NTP can be produced while pressure increases within the cylinder during the compression stroke of the piston. For the reasons described at least in relation to FIG. 5, the piston-cylinder assembly 700 can have a long stroke configuration and / or can be included in a four-stroke engine.

[0084] FIG. 8 shows a representation of a fourth example piston-cylinder assembly 800 included in a transient reactor system and having piston-mounted electrodes and catalyst, according to an embodiment. More specifically, FIG. 8(a) shows the piston-cylinder assembly 800 during an intake stroke of the piston, where the piston can be disposed at a lower position within the cylinder, the intake valve(s) can be open, and the exhaust valve(s) can be closed. FIG. 8(b) shows the piston-cylinder assembly 800 at (or substantially near) an end of compression stroke, where the piston can be disposed at (or substantially near) top dead center (TDC) within the cylinder and both the intake valve(s) and the exhaust valve(s) can be closed. The piston-cylinder assembly 800 can be functionally similar to the piston-cylinder assembly 600 FIG. 6; however, in the piston-cylinder assembly 800, the high voltage electrode, the ground electrode, and the catalyst can be disposed on the piston crown rather than the cylinder head. The piston-cylinder assembly 800 can further include a high voltage trigger. Although326310289 23Agent’s File Ref. EMVL-003 / 01WG 353000-2012 the high voltage trigger in FIG. 8 is shown disposed proximate to the top (head) of the cylinder and distal to the bottom (base) of the cylinder, in some implementations, the high voltage trigger (e.g., a first electrical contact) can be disposed further from the cylinder head and closer to the cylinder base. The electrical contact can be elongated to trigger discharge while a second contact disposed on the moving piston is disposed between endpoints of the elongated first contact. This alternative configuration can permit the piston-cylinder assembly 800 to produce NTP as cylinder pressure increases during the compression stroke. As a result of the intake and exhaust valves being disposed at the cylinder head in the piston-cylinder assembly 800, the piston-cylinder assembly 800 can be included in a four-stroke engine.(0085) FIG. 9 shows a representation of a fifth example piston-cylinder assembly 900 included in a transient reactor system and having a head-mounted electrode and a pistonmounted catalyst, according to an embodiment. More specifically, FIG. 9(a) shows the pistoncylinder assembly 900 during an intake stroke of the piston, where the piston can be disposed at a lower position within the cylinder, the intake valve(s) can be open, and the exhaust valve(s) can be closed. FIG. 9(b) shows the piston-cylinder assembly 900 at (or substantially near) an end of compression stroke, where the piston can be disposed at (or substantially near) top dead center (TDC) within the cylinder and both the intake valve(s) and the exhaust valve(s) can be closed. As shown in FIG. 9, a high voltage electrode can be disposed at the cylinder head, and a ground electrode and catalyst can be disposed at the piston crown. Although FIG. 9 shows the high voltage electrode being fully (or substantially disposed) between the ground electrode while the piston is at (or substantially near) TDC, in some embodiments, the piston-cylinder assembly 900 can be configured such that the high voltage electrode is disposed between the ground electrode while the piston undergoes a compression stroke (e.g., before the piston reaches TDC). A compute device (e.g., that is functionally and / or structurally similar to the compute device 110 of FIG. 1) can actuate a switch to energize the high voltage electrode, causing NTP to be produced while pressure increases within the cylinder as the piston approaches TDC.FIG. 10 shows a representation of a rotary piston assembly 1000 (e.g., a Wankel engine piston, an eccentric rotary engine piston, etc.) included in a transient reactor system and having stator housing mounted electrodes and catalyst, according to an embodiment. More specifically, FIG. 10(a) shows the rotary piston assembly 1000 in an intake configuration, and FIG. 10(b) shows the rotary piston assembly 1000 in a compression configuration (e.g., at or near the end of a compression state). The high voltage electrode can326310289 24Agent’s File Ref. EMVL-003 / 01WG 353000-2012 produce discharge while the rotary piston assembly 1000 is in the compression configuration (e.g., as shown in FIG. 10(b)).

[0086] FIG. 11 shows a schematic representation of a transient reactor system 1100, according to an embodiment. The transient reactor system can functionally and / or structurally similar to the transient reactor system 100 of FIG. 1. The transient reactor system 1100 can include an internal combustion engine (ICE) (e.g., that is functionally and / or structurally similar to the internal combustion engine 150 of FIG. 1) and an ECU (e.g., that is functionally and / or structurally similar to the compute device 110 of FIG. 1 and / or the compute device 201 of FIG. 2). The ICE can include an engine cylinder (e.g., that is functionally and / or structurally similar to the cylinder 152 of FIG. 1), a piston (e.g., that is functionally and / or structurally similar to the piston 158 of FIG. 1), a high voltage electrode (e.g., that is functionally and / or structurally similar to the plasma generator 120 of FIG. 1), a crankshaft position sensor (e.g., that is functionally and / or structurally similar to the crankshaft position sensor 160 of FIG. 1), and a pressure sensor (e.g., that is functionally and / or structurally similar to the pressure sensor 156 of FIG. 1).

[0087] In some implementations, the high voltage electrode can be configured to produce a plurality of discharges at a given time (e.g., rather than via a single discharge channel) to cause the discharges to be distributed across a catalyst. In some implementations, the high voltage electrode can be configured to produce periodic pulses (e.g., having a length of 10 ns, more than 10 ns, less than 1 ms, etc.). The high voltage electrode can produce the pulses at a frequency of, for example, 10 kHz, more than 10 kHz, etc. In some implementations, the high voltage electrode can be configured to produce corona-like discharges (also referred to herein as “streamers”) rather than, for example, nanosecond sparks. While a streamer can deliver less energy than an arc-type discharge, a streamer can facilitate a more uniform discharge than an arc -type discharge. In some implementations, as described further herein, the high voltage electrode can produce discharges during at least part of a compression cycle and / or continue producing discharges during at least part of an expansion cycle. The transient reactor system can be configured to supply alternating current (AC) or direct current (DC) to produce streamers.

[0088] In some implementations, to facilitate local breakdown in the presence of an electric field produced by the electrodes, a catalyst bed included in the transient reactor system 1100 can be configured to define a field enhancement region. For example, catalyst particles can have sharp points and / or edges to cause field concentration at the points and / or edges (e.g., as326310289 25Agent’s File Ref. EMVL-003 / 01WG 353000-2012 a result of the dielectric constant for the catalyst being different than that of the gas). Field concentration around these features of the catalyst particles can cause a streamer to be produced from those features. By providing a substantially uniform distribution of the field enhancement features throughout the catalyst bed, the transient reactor system 1100 can produce a substantially uniform distribution of steamers across the catalyst bed.[0089J Alternatively or in addition, in some implementations, the transient reactor system 1100 can include a plurality of conducting elements that can be distributed throughout the catalyst bed to improve the distribution of streamers. These conducting elements can be configured to surround the catalyst (e.g., catalyst pellets and / or particles) and / or be disposed among the catalyst (e.g., between the pellets and / or particles). These conducting elements can have sharp points and / or edges to enhance a local electric field and, as a result, produce local breakdown. The conducting elements can be bare and / or covered with an electrically insulating layer to prevent percolation and / or shortening of the electrodes.[0090J To facilitate high frequency, nanosecond-duration plasma discharge within the cylinder at a desired time, the transient reactor system 1100 can include an ECU that can be configured to use signals from engine sensors as feedback to control discharge via the high voltage electrode. These engine sensors can include a crankshaft encoder and / or an in-cylinder pressure transducer. The crankshaft encoder can encode a crank angle measurement to indicate piston position, and the in-cylinder pressure transducer can encode in-cylinder pressure. In at least some instances, these two signals can be strongly correlated. Based on these feedback signals, the ECU (or another compute device) can be configured to cause discharge when the engine has a desired pressure and / or crank angle.[0091J FIG. 12 shows a schematic representation of piston-cylinder assemblies having membranes configured to separate a catalyst from oil and / or other lubricants to prevent contamination of the catalyst, according to an embodiment.

[0092] Unlike a typical automotive engine, an engine configured for use in a transient reactor system (also referred to herein as a reactor engine) can, in typical operation, operate at a constant speed and / or load and, as a result, can undergo reduced friction force variation as compared to an automotive engine. Moreover, as compared to a typical automotive engine, a reactor engine can operate at a slower speed to account for residence time of chemical synthesis, low load, and / or a slower chemical conversion rate than the rate of combustion of an air-fuel mixture in an automotive engine. As a result of reduced variation in friction, lower326310289 26Agent’s File Ref. EMVL-003 / 01WG 353000-2012 operating speed, and / or lower load, a reactor engine can exclude an engine liner that is typically included in an automotive engine. Moreover, the reactor engine can further exclude lubricant injection and / or spray systems that lubricate a connecting rod, piston, bearing, and / or liner of the engine. Instead, the reactor engine can include a lubricant delivery system that can be dedicated to the connecting rod, piston, and / or bearing This configuration can prevent lubricant splash that may enter the reaction chamber during piston motion. To reduce friction between piston rings and a cylinder wall, a chemical and / or metallic coating can be applied to the piston rings and the liner. These coatings can have sufficiently high tensile strength and / or sufficient thermal conductivity to prevent wear of the piston rings and / or line.[0093 J In some embodiments, the reactor engine can include piston rings having a modified radial tension as compared to a typical automotive engine . For example, in a typical automotive engine, the tension of the piston rings is configured to balance friction and lubricant consumption. Lower tension can result in less friction and higher efficiency but also a larger gap and, hence, more lubricant consumption. In a reactor engine, friction can be a lesser concern than lubricant consumption. Therefore, the reactor engine can include piston rings having higher radial tension.[0094J To minimize poisoning of the catalyst from lubricant that enters the reaction chamber (e.g., the cylinder), the lubricant can be configured to be compatible with the reaction chemistry. For example, the lubricant can exclude oil additives having substantial levels of organometallics, detergents, wetting agents, and / or stabilizers, which may interfere with catalysis. Instead, the lubricant can include nonvolatile base oils, such as mineral oil (e.g., polydimethylsiloxane (PDMS)) and / or a heavy hydrocarbon blend. Because a reactor engine can, in at least some instances, operate at a relatively low speed (e.g., below 2400 RPM) and at consistent operating conditions (e.g., less variability in feed mixtures, speeds, temperatures, etc., as compared to typical operation of an automobile), a reactor engine can operate with fewer additives relative to automotive applications.[0095 J In some implementations, the catalyst can be disposed within the cylinder such that the catalyst has a reduced likelihood of being contaminated by oil droplets from interaction between the piston and cylinder walls. Generation of oil droplets and / or aerosols can occur, for example, during low speed and high load operation and / or if the reactor engine is a supercharged engine. The oil droplets and / or aerosols can be produced from the piston / ring crevice and / or or from the piston crown. To prevent oil from contaminating the catalyst, a cylinder can be configured to include a lipophobic membrane that can be configured to326310289 27Agent’s File Ref. EMVL-003 / 01WG 353000-2012 selectively permit reactant gasses to pass. A lipophobic coating can include, for example, a chemical coating and / or physical texturing of a membrane using plasma etching, laser etching, and / or chemical etching. The membrane can include a porous metallic substrate (e.g., stainless steel, nickel, copper, aluminum, and / or specialty alloys) to maintain temperature stability.[0096 J In some embodiments, the reactor engine can operate in cyclic and / or staged modes, alternating and / or switching between synthesis and reconditioning states. For example, the reactor engine can initiate plasma-assisted oxidation cycles periodically (e.g., based on a predetermined number of operations, a predetermined engine-run time, and / or the like) and / or based on sensor feedback, to remove carbonaceous and / or sulfur-containing residues from catalysts and electrodes using controlled pulses in oxidizing environments.10097 J FIG. 12 more specifically shows various example membranes that include metal substrates. For example, FIG. 12(a) shows a metal frit substrate, and FIG. 12(b) shows a mesh and / or perforated sheet substrate. Other substrates not shown in FIG. 12 can include, for example, a sponge-like material and / or any other surface substrate configured to increase contact angle between the substrate and an oil droplet. This structure can be created, for example, by applying nanostructured silica (which can be temperature stable) and / or by etching patterns into the substrate using chemical etching, plasma etching, and / or laser etching techniques. In some implementations, as shown in FIGS. 12(c) and 12(d), a piston-cylinder assembly can include a secondary packed bed that can be configured to prevent oil from contacting the catalyst. For example, FIG. 12(c) shows absorbent material disposed over the catalyst. The absorbent material can be configured to capture oil droplets while permitting reactant gas to diffuse through the catalyst. The absorbent material can be sacrificial (e.g., such that it can be replaced with the catalyst bed) or regenerated in a regeneration cycle. FIG. 12(d) shows a hydrogenolysis catalyst coupled to the catalyst bed. The hydrogenolysis catalyst can be used if, for example, the reactor engine uses an excess of hydrogen. In this case, the hydrogenolysis catalyst can break down oil into smaller hydrocarbon specific that do not interfere with the chemistry of the reaction.[00981 FIG. 13 shows a schematic representation of a piston-cylinder assembly that is operably coupled to an external volume, according to an embodiment. FIG. 14 shows a schematic representation of a plurality of piston-cylinder assemblies that is operably coupled to an external volume, according to an embodiment. As described above, the external volume can facilitate longer residence times for slower reactions that may not be completed during a single cylinder cycle. The piston-cylinder assembly can be configured to operate in a split cycle326310289 28Agent’s File Ref. EMVL-003 / 01WG 353000-2012 mode, where pressurized reactant gas can be produced during a compression stroke, and the reactant gas can then be fed into the external volume having the catalyst, plasma electrode, or both. The reactor effluent can then be expanded during an expansion stroke in the same cylinder (as shown in FIG. 13) or in a second cylinder (as shown in FIG. 14), to recover work and / or improve energy efficiency.[0099J The external volume can be configured based on the reaction being performed. For example, for at least some gas-phase reactions, the reactor can include a tube having (or excluding) a plasma electrode disposed within a volume of the tube and a catalyst in an annular volume defined by the tube and the electrode. This configuration can be referred to as a plug flow design. To control temperature, the tube can be disposed within a heat exchanger having (1) a heated fluid (e.g., steam) for performing endothermic reactions and / or (2) a cooling fluid for exothermic reactions. Optionally, an oil and / or particulate filter can be disposed upstream of the external volume to prevent engine lubricant from contacting the catalyst. Alternatively or in addition, a particulate filter can be disposed downstream of the external volume to prevent dust produced by catalyst attrition from interfering with downstream processes. The external volume can further include a fluidized bed (e.g., for use in fast gas-phase reactions with fast catalyst deactivation) and / or stirred tank and / or slurry reactors (e.g., for use in liquid-phase and / or gas-liquid reactions).[0100J FIG. 15 shows a schematic representation of a transient reactor system 1500 that includes a compute device, according to an embodiment. The compute device can be functionally and / or structurally similar to the compute device 110 of FIG. 1 and / or the compute device 201 of FIG. 2. The compute device can include, for example, an ECU configured to trigger a plasma power supply, via a network and a plasma controller, to generate and / or sustain plasma within a single cylinder reactor. This triggering can be based on a signal received via the network from a crank-shaft position sensor. As a result, the compute device can cause the plasma power supply to generate plasma based on a compression state of the single cylinder reactor, as described further herein.[0101 | FIG. 16 shows a schematic representation of a transient reactor system 1600 that includes an external volume, according to an embodiment. The external volume can be functionally and / or structurally similar to the external volume described herein at least in relation to FIG. 13 and / or FIG. 14. The transient reactor system 1600 includes a mechanical actuator (e.g., a cam on a camshaft of an ICE) that is configured to trigger a valve(s) to an326310289 29Agent’s File Ref. EMVL-003 / 01WG 353000-2012 external volume to permit flow of gas (e.g., compressed gas) to and / or from a cylinder volume, as described further herein.

[0102] FIG. 17 shows a schematic representation of a transient reactor system 1700 that includes a camshaft, according to an embodiment. More specifically, the transient reactor system 1700 includes a mechanical actuator (e.g., a cam on the camshaft of an ICE) configured to trigger pulse generation via the plasma power supply. In some implementations, the transient reactor system 1700 can be configured to generate a continuous trigger pulse at a predetermined frequency (e.g., that is determined based on the frequency of a cylinder cycle and / or that is predetermined and remains fixed independent of RPM). The cam coupled to the ICE (e.g., the cam mechanically linked to the camshaft) can be configured to close a circuit to direct the trigger pulse to the plasma power supply (e.g., a pulse generator) for the duration of the cylinder cycle that activated plasma is desired.[0103 J Examples of computer code include, but are not limited to, micro-code or microinstructions, machine instructions, such as produced by a compiler, code used to produce a web service, and files containing higher-level instructions that are executed by a computer using an interpreter. For example, embodiments can be implemented using Python, Java, JavaScript, C++, and / or other programming languages and development tools. Additional examples of computer code include, but are not limited to, control signals, encrypted code, and compressed code.

[0104] The drawings primarily are for illustrative purposes and are not intended to limit the scope of the subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the subject matter disclosed herein can be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally similar, and / or structurally similar elements).[0.105] The acts performed as part of a disclosed method(s) can be ordered in any suitable way. Accordingly, embodiments can be constructed in which processes or steps are executed in an order different than illustrated, which can include performing some steps or processes simultaneously, even though shown as sequential acts in illustrative embodiments. Put differently, it is to be understood that such features can not necessarily be limited to a particular order of execution, but rather, any number of threads, processes, services, servers, and / or the like that can execute serially, asynchronously, concurrently, in parallel, simultaneously,326310289 30Agent’s File Ref. EMVL-003 / 01WO 353000-2012 synchronously, and / or the like in a manner consistent with the disclosure. As such, some of these features can be mutually contradictory, in that they cannot be simultaneously present in a single embodiment. Similarly, some features are applicable to one aspect of the innovations, and inapplicable to others.[0106J Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the disclosure. That the upper and lower limits of these smaller ranges can independently be included in the smaller ranges is also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.

[0107] The phrase “and / or,” as used herein in the specification and in the embodiments, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements can optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.|0108] As used herein in the specification and in the embodiments, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the embodiments, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only326310289 31Agent’s File Ref. EMVL-003 / 01WG 353000-2012 one of,” or “exactly one of.” “Consisting essentially of,” when used in the embodiments, shall have its ordinary meaning as used in the field of patent law.[01091 As used herein in the specification and in the embodiments, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements can optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.[0110} In the embodiments, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.Some embodiments described herein relate to a computer storage product with a non-transitory computer-readable medium (also can be referred to as a non-transitory processor-readable medium) having instructions or computer code thereon for performing various computer-implemented operations. The computer-readable medium (or processor- readable medium) is non-transitory in the sense that it does not include transitory propagating signals per se (e.g., a propagating electromagnetic wave carrying information on a transmission medium such as space or a cable). The media and computer code (also can be referred to as code) can be designed and constructed for the specific purpose or purposes. Examples of non- transitory computer-readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, and magnetic tape; optical storage media such as Compact326310289 32Agent’s File Ref. EMVL-003 / 01WG 353000-2012Disc / Digital Video Discs (CD / DVDs), Compact Disc -Read Only Memories (CD-ROMs), and holographic devices; magneto-optical storage media such as optical disks; carrier wave signal processing modules; and hardware devices that are specially configured to store and execute program code, such as Application-Specific Integrated Circuits (ASICs), Programmable Logic Devices (PLDs), Read-Only Memory (ROM) and Random-Access Memory (RAM) devices. Other embodiments described herein relate to a computer program product, which can include, for example, the instructions and / or computer code discussed herein.[0112| Some embodiments and / or methods described herein can be performed by software (executed on hardware), hardware, or a combination thereof. Hardware modules can include, for example, a processor, a field programmable gate array (FPGA), and / or an application specific integrated circuit (ASIC). Software modules (executed on hardware) can include instructions stored in a memory that is operably coupled to a processor and can be expressed in a variety of software languages (e.g., computer code), including C, C++, Java™, Ruby, Visual Basic™, and / or other object-oriented, procedural, or other programming language and development tools. Examples of computer code include, but are not limited to, micro-code or micro-instructions, machine instructions, such as produced by a compiler, code used to produce a web service, and files containing higher-level instructions that are executed by a computer using an interpreter. For example, embodiments can be implemented using imperative programming languages (e.g., C, Fortran, etc.), functional programming languages (Haskell, Erlang, etc.), logical programming languages (e.g., Prolog), object-oriented programming languages (e.g., Java, C++, etc.) or other suitable programming languages and / or development tools. Additional examples of computer code include, but are not limited to, control signals, encrypted code, and compressed code.326310289 33

Claims

Agent’s File Ref. EMVL-003 / 01WO 353000-2012CLAIMSWhat is claimed is:

1. An apparatus, comprising: a first chamber that defines a variable volume; an actuator configured to transiently vary a pressure within the variable volume of the first chamber; and an energy source configured to produce plasma in at least one of the variable volume of the first chamber or a volume of a second chamber without causing combustion, the energy source in selective fluid communication with the variable volume of the first chamber.

2. The apparatus of claim 1, further comprising: a trigger configured to trigger the energy source based on a position of the actuator.

3. The apparatus of claim 1 or 2, further comprising: an inlet valve configured to cause reactant gas to enter the variable volume; and an outlet vale configured to allow one of compressed reactant gas to enter the volume of the second chamber or a product gas different from the reactant gas to be discharged from the variable volume.

4. The apparatus of any one of claims 1-3, wherein: the actuator includes a reciprocating piston, at least a portion of the reciprocating piston being disposed within the first chamber.

5. The apparatus of any one of claims 1-4, wherein the energy source includes a plasma generator configured to produce the plasma within the variable volume of the first chamber, the apparatus further comprising: a catalyst disposed in the variable volume of the first chamber.

6. The apparatus of any one of claims 1-5, further comprising: a catalyst disposed in the volume of the second chamber, the plasma produced by the energy source at least one of:326310289 34Agent’s File Ref. EMVL-003 / 01WO 353000-2012 being produced in the variable volume of the first chamber and flowing to the volume of the second chamber, or being produced in the volume of the second chamber.

7. The apparatus of any one of claims 1-6, wherein the energy source includes: a high-voltage electrode disposed in at least one of the variable volume of the first chamber or the volume of the second chamber; and at least one of a counter-electrode or a grounded structure disposed in the at least one of the variable volume of the first chamber or the volume of the second chamber.

8. The apparatus of any one of claims 1-7, further comprising: one or more sensors configured to monitor at least one of gas composition, pressure, temperature, electrical -discharge characteristics, or vibration in at least one of the first chamber or the second chamber.

9. The apparatus of any one of claims 1-8, further comprising: a control unit configured to initiate a regeneration cycle in at least one of the first chamber or the second chamber; and a sensor configured to detect, in the at least one of the first chamber or the second chamber, at least one of performance degradation, fouling, or a deviation from a predetermined operating condition, the control unit being configured to initiate the regeneration cycle based on the at least one of the performance degradation, the fouling, or the deviation from the predetermined operating condition.

10. The apparatus of claim 9, wherein the regeneration cycle includes at least one of: introduction of a first gas into the at least one of the variable volume of the first chamber or the volume of the second chamber, the first gas being different from a second gas disposed in the at least one of the first chamber or the second chamber before the regeneration cycle; or application of at least one of a plasma discharge or microwave discharge to remove accumulated deposits from at least one of: a surface of the at least one of the variable volume of the first chamber or the volume of the second chamber, or a catalyst structure disposed in the at least one of the variable volume of the first chamber or the volume of the second chamber.326310289 35Agent’s File Ref. EMVL-003 / 01WG 353000-201211. The apparatus of any one of claims 1-10, wherein: the energy source includes a microwave energy source; and the plasma includes non-thermal plasma generated by the microwave energy source by producing microwave radiation in the at least one of the variable volume of the first chamber or the volume of the second chamber and during at least a portion of a compression cycle associated with the actuator.

12. The apparatus of claim 11, wherein at least one of: the microwave energy source operates at a frequency between about 0.4 GHz and about 5 GHz; or the microwave radiation includes one or more pulses having a duration between about 1 microsecond and about 1 millisecond and a duty cycle between about 1% and about 50%.

13. The apparatus of claim 11 or 12, further comprising: at least one of a waveguide, a coaxial probe, or a dielectric window, configured to direct the microwave radiation from the microwave energy source to the at least one of the variable volume of the first chamber or the volume of the second chamber.

14. The apparatus of any one of claims 11-13, further comprising: a catalyst support disposed within the at least one of the variable volume of the first chamber or the volume of the second chamber and including a dielectric material configured to alter a microwave field distribution associated with the microwave radiation and promote localized formation of the plasma.

15. A method, comprising: causing a reactant gas to enter a reaction chamber; transiently varying a pressure of the reactant gas; based on the pressure of the reactant gas being below a threshold above which plasma cannot be initiated, generating a plasma within the reaction chamber; and in response to the generating, discharging, from the reaction chamber, a product gas that is different from the reactant gas.

16. The method of claim 15, wherein causing the reactant gas to enter the reaction chamber includes:326310289 36Agent’s File Ref. EMVL-003 / 01WO 353000-2012 opening, based on a crankshaft associated with the reaction chamber being in a first orientation, an intake valve of the reaction chamber to cause the reaction chamber to breathe in the reactant gas; and closing the intake valve based on the crankshaft being in a second orientation different from the first orientation.

17. The method of claim 16, wherein the opening the intake valve and the closing the intake valve is mechanically facilitated by a cam coupled to the crankshaft.

18. The method of any one of claims 15-17, further comprising: excluding causing combustion in the reaction chamber between the causing the reactant gas to enter the reaction chamber and the discharging the product gas.

19. The method of any one of claims 15-18, wherein the plasma includes a non-thermal plasma (NTP).

20. The method of any one of claims 15-19, wherein generating the plasma includes triggering a plasma generator to generate a plurality of nanosecond pulsed discharges.

21. The method of any one of claims 15-20, wherein generating the plasma includes generating the plasma having at least one of a pulse timing or an energy, that is based on the pressure of the reactant gas.

22. The method of any one of claims 15-21, wherein transiently varying the pressure of the reactant gas includes causing a reciprocating piston to actuate during a compression stroke.

23. The method of any one of claims 15-22, wherein transiently varying the pressure of the reactant gas occurs within a cylinder that includes the reaction chamber.

24. The method of any one of claims 15-23, wherein transiently varying the pressure of the reactant gas occurs within a cylinder that defines an internal volume that is different from the reaction chamber.

25. A non-transitory processor-readable medium storing instructions that, when executed by a processor, cause the processor to:326310289 37Agent’s File Ref. EMVL-003 / 01WO 353000-2012 receive a first signal that encodes at least one of: a position measurement indicating that a position of a piston of a plasma- assisted chemical synthesis reactor is associated with a compression stroke, or a pressure measurement indicating that a pressure within a cylinder of the plasma-assisted chemical synthesis reactor is below a threshold above which a plasma cannot be initiated; and in response to receiving the first signal, cause a second signal to be sent to a plasma generator to produce a plasma associated with a gas that is within the cylinder.

26. The non-transitory processor-readable medium of claim 25, wherein the instructions, when executed, are further configured to cause the processor to: cause a third signal to be sent to a valve to cause at least one of the gas or the plasma to flow from the cylinder to a reaction chamber, the plasma generator being configured to produce the plasma within at least one of the cylinder or the reaction chamber.

27. The non-transitory processor-readable medium of claim 25 or 26, wherein the instructions, when executed, are further configured to cause the processor to: cause the second signal to be sent to the plasma generator based on the first signal indicating that the position of the piston is associated with one of before a compression peak, at the compression peak, or after the compression peak.326310289 38

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