Radial counterflow muffler for NO reduction and pollutant collection

A scrubbing muffler for internal combustion engines comprises coaxial counter-rotating disk pairs stacked in a cascade. Acoustic pulses are attenuated by doing work and dissipated by the circuitous path through the dynamic cascade. A motor and/or Venturi effect from slipstream over a vehicle assists exhaust and reduces backpressure for greater fuel economy. Exhaust gas fed at the axis is sheared between the disks of the first stage of the cascade as it passes radially outward into a shrouding tank disposed about the cascade. Vortex rebound at the tank wall advects flow radially inward back through the workspace between the first stage disks to axial extraction as feed for the second stage of the cascade. N2 and H2O, along with CO and NO, can pass radially inward to successive stages. Soot and CO2 stay in the tank. NO and CO are reduced at a Faraday disk cathode.

BACKGROUND

1. Technical Field

The present disclosure relates to mufflers and means for diminishing the noise and emissions of internal combustion engines such as catalytic converters and soot collectors. It also relates to electrolytic reduction of nitric oxide (NO) and to collection of soot and carbon dioxide from internal combustion engines.

2. Prior Art

Internal combustion engines produce exhaust streams which contain pollution and noise. Mufflers have been used to reduce the noise out of the exhaust pipe, but the mufflers do not capture the pollution in the exhaust stream, and reduce fuel efficiency by causing backpressure.

Noise from internal combustion engines results from acoustic pulses of the engine exhaust stream. These acoustic exhaust pulses conventionally are dissipated by a muffler, which conventionally is a static device which forces the exhaust gas to flow through a tortuous path among baffles. The acoustic pulses of hot and dirty exhaust from the engine, which otherwise would produce a loud sound out of the exhaust pipe, are broken up and their linear momentum becomes diffused in isotropic turbulence. Backpressure due to this isotropic turbulence in the tortuous flow path means that the engine must work harder to push the exhaust through to discharge, raising the fuel requirements and increasing the heat and wear on the engine. A need exists for a way to reduce backpressure without increasing noise out of the exhaust pipe.

The faster an exhaust pulse moves, the better it can suck out the spent gases during valve overlap, called exhaust pulse scavenging. Because conventional muffler design obstructs flow, exhaust gas pulses cannot move fast enough to create low pressure wakes to evacuate the cylinders and accomplish exhaust pulse scavenging.

Reetz, U.S. Pat. No. 1,109,702 (1914) and Jackson, U.S. Pat. No. 2,479,165 (1949) teach a rotatable baffle comprising helical blades and having an axis of rotation along the path of flow into and out of the muffler (axial exhaust flow). Chang, U.S. Pat. No. 6,343,673 (2002) teaches a multibladed turbine having its axis of rotation along the axial exhaust flow path through the turbine blades.

Corless, U.S. Pat. No. 2,003,500 (1935) and U.S. Pat. No. 2,518,869 (1950), teaches a rotatable baffle actuated by exhaust flow radially inward to its axis of rotation. Chimento, U.S. Pat. No. 2,958,506 (1960) also teaches a radial flow turbine. These radial flow turbine references teach an impulse turbine fed at the rotor periphery by engine exhaust. Wall, U.S. Pat. No. 7,331,422 (2008) teaches a vortex muffler having a stationary fan disposed along an axial flow path for imparting swirl to an exhaust gas stream and thereby assisting discharge into the atmosphere

Cumins, U.S. Pat. No. 5,772,235 teaches deflectors for lowering the pressure in the exhaust stream. Yates et al., U.S. Pat. No. 4,970,859 teaches a deflection shield which has the effect of lowering the pressure in the exhaust system and directing the exhaust soot away from a truck cab.

Soot, CO2, and NOx (mainly nitric oxide, NO) as well as metals and volatile organic compounds (VOCs), such as polycyclic aromatic hydrocarbons, BTEX and formaldehyde, are pollutants in the exhaust gas stream from gasoline or diesel internal combustion engines. Natural gas internal combustion engines also have CO2and NOx pollution.

Nitric oxide is thermodynamically unstable, so its reduction to form harmless N2and O2only takes a little energy input. Conventionally nitric oxide is reduced to N2and O2by catalytic converters comprising platinum, an expensive metal. Urea is another way, but it entails a chemical process which adds weight and occupies space. A need exists for an alternative to precious metal catalytic converters for reducing nitric oxide in vehicle exhaust.

Soot includes diesel particulate emissions. Particulate emissions cannot be filtered from vehicle exhaust streams economically because of the large pressure drop through any dead-end filter. Dead-end filtration adds yet another flow impedance with consequent backpressure and loss of fuel efficiency, and filters tend to clog, requiring frequent replacement. A need exists for a way to capture and concentrate soot from exhaust in a continuous process.

Carbon dioxide in the exhaust streams of cars and trucks is a major contributor to the accumulation of carbon dioxide in the atmosphere, which has implications for global climate. Amine scrubbing and cryogenic distillation are unsuitable for carbon dioxide capture in vehicles, and membrane filters are not feasible due to the soot and water in the exhaust gas. Again, dead-end filters such as membranes entail a large backpressure which reduces fuel efficiency.

Most of exhaust gas is harmless N2and water vapor (collectively referred to as “nitrogen ballast”) so stripping the nitrogen ballast would concentrate the pollutants and thus aid collection and treatment of the noxious constituents, such as soot, CO2and nitric oxide. Nitrogen gas (N2) has a molecular weight of only 28 g/mol, and H2O is lighter still, at 18 g/mol, while CO2is 44 g/mol, NO2is 46 g/mol, and soot is much denser than these gases. VOCs are also relatively heavy gases. This task is aided by the difference in molecular weight of the constituents of exhaust gas, which allows for centrifugal gas separation in the open von Karman geometry. See McCutchen, U.S. Pat. No. 7,901,485 (2011).

SUMMARY

In an embodiment, exhaust gas from an internal combustion engine is fed through an axial feed port and radially expanded through a radial workspace between opposed coaxial counter-rotating disks. Vanes on the turbines define channels through which the feed flows radially outward, diffusing its momentum into the turbines. Counter-rotation of the turbines creates a shear layer between them, and in this shear layer a sink flow is radially inward toward the turbines' common axis of rotation. A shrouding wall disposed about the periphery of the turbines rebounds nitrogen ballast radially inward through the shear layer to axial extraction into a succession of stages in a cascade.

Heavier constituents, such as soot, CO2, and NO2, are collected from the periphery of the disks. N2and H2O, because of their lesser molecular weight, flow through the shear layer radially inward and are extracted through an axial extraction port. Nitric oxide (NO) flows with the nitrogen ballast radially inward and up through the cascade because its molecular weight (30 g/mol) is approximately the same as N2(28 g/mol). The NO, having been separated from the CO2and other pollutants, is then reduced by electrolysis.

For electrolysis, rotation of at least one disk through an axial magnetic field turns an annular portion of the disk downstream in the cascade into an electrode (cathode) for reduction of NO. Because most of the CO2has been previously separated out and collected in the shrouding tank, this cathode will is less likely to produce carbon monoxide in the final output stream.

Feed of exhaust gas from an internal combustion engine is continuous through an axial feed port in one turbine/impeller disk, and the extraction of the nitrogen ballast (and NO) is through an axial extraction port in the other disk. A baffle separates the axial feed port from the axial extraction port. A cascade of such devices, each stage in the cascade fed by the axial extraction port of an upstream device, provides means for absorbing the momentum of the exhaust gas and performing complete gas and particulate separation. Acoustic pulses are converted to motive force for the counter-rotation of the turbines of the cascade, so the noise from the engine is dissipated not in the isotropic turbulence of a conventional muffler but in the anisotropic turbulence of this dynamic cleaning muffler.

A long residence time in the workspace effectively separates pollutants from the nitrogen ballast. Centrifugal separation occurs in vortices forced in the shear layer between the turbines, and multi-scale coherent structures in the shear layer integrate the tiny separation effects of these vortices and allow for the continuous extraction of nitrogen and water vapor from the exhaust gas, thus concentrating the soot, CO2, NO2and VOCs, which collect in the periphery of the disks.

The soot is concentrated, while the carbon dioxide can go into a separate peripheral gas vent. Electrostatic charge attracts soot to a screen over a hopper which is charged as an anode, as in a conventional electrostatic precipitator. The soot concentrates at the periphery of the turbines and at the wall of the shrouding tank, eventually migrating down through the charged screen and into a hopper. The captured carbon dioxide is clean and concentrated enough to be compressed for later disposal.

A motor assists exhaust flow through the cascade, and under some circumstances the motor becomes a generator, for example in long-haul trucks, harvesting power to run cooling equipment or compressors for CO2.

Counter-rotating disks such as this can be turned by a motor, by vanes driven by the passing wind outside a vehicle, or by the energy contained in the exhaust stream.

DRAWING REFERENCE NUMERALS

1Exhaust gas input stream from engine2Axial feed port3Baffle4Workspace5Lower radial turbine6Vane6aImpeller vane7Upper radial turbine8Axial extraction port9Shrouding wall10Input conduit11First rotation direction12Second opposite rotation direction13Central drive spindle14Motor15Soot hopper16Conductive disk17Magnet18Cathode19Outlet of shrouding tank20Atmospheric outlet stream21Exhaust gas input stream22Intake vent23Baffle24Workspace25Lower disk26Axial intake port27Upper disk28Axial outlet port29Axial outlet vent30Axial outlet stream31Motion of upper disk32Motion of lower disk33Inlet screw pump34Outlet screw pump35Lighter constituents36Heavier constituents37Axis of rotation38Periphery39Angled annular deflector wall40Embedded vanes in deflector wall41Heavy particulates42Outlet in disk for soot43Annular soot collection pipe44Soot collection vertical pipe45Gases on periphery46Heavier gaseous elements47Opening for peripheral gases48Static annular gas collection pipe49Gas collection vertical pipe50Pad for triboelectric charging51Outer casing51aRotation linkage52Open scoop vane53Closed shield vane54Inter-disk gear55Gear tooth rack on the baffle56Vane between baffle and lower disk57Rigid shaft for gear58Central support shaft59Thrust bearings and centering support structure for lower disk60Thrust bearings and centering support structure for upper disk61Cross section plane A below the lower disk62Cross section plane B above the lower disk63Cross section plane C below the upper disk64Cross section plane D above the upper disk65Slipstream from the motion of a vehicle66Induced motion of the vanes67Windshield68Outer gear69Outer gear track70Outer gear shaft71Path of exhaust72Vane casing connection to top impeller73Soot compression chamber74Soot chunks75Soot compression motor76Main soot collection pipe78Gas pump79Main gas collection pipe80Gas storage tank81Driving vane underneath baffle82Vane on lower disk83Vane on upper disk84Vortex85Peripheral gap86Peripheral shield87Enclosing Tank88Interior of tank89Boundary layer90Shear Layer91Vortex axis92Rotating drum93Planetary gears94Escape valve95Anode96Cathode

DETAILED DESCRIPTION

FIG. 1shows a cross section of the left half of a single pair of counter-rotating radial turbines in the first stage of a cascade. An exhaust gas input stream1from an internal combustion engine enters through an axial feed port2which is at the center of a lower radial turbine5. The input stream is partially blocked by a baffle3, disposed between the axial feed port2at the center of the lower radial turbine5and an axial extraction port8at the center of the upper radial turbine7. The vanes6on the disks can be radial turbine vanes that are actuated by a radially outward flow from the axis of rotation a—a through the workspace4between the radial turbines, or they may advect the outward flow when the disk is turned by suitable means, such as a motor. The term radial turbine herein refers to the combination of the disk and one or more vanes, whether the turbine advects or is advected by the flow through the workspace4.

Each of the disks5,7comprises an array of vanes6extending into the radial workspace4, and in this case the vane6attaches the baffle and the lower disk5together so they will rotate together. The exhaust gas expands through a radial workspace4between the lower disk5and an upper disk7. The opposite curvature of the radial vanes on the turbines causes counter-rotation of the disks5,7in opposite directions17and19about a common axis of rotation a—a as the exhaust gas expands between them and pushes against the vanes. By doing work turning the disks5,7the exhaust gas loses enthalpy and its acoustic pulses are dissipated so engine noise is abated.

Due to counter-rotation of the coaxial disks5,7a shear layer forms between them in the workspace4. The shear layer comprises a vortex network for separation of the lighter and heavier constituents of the feed by enhanced centrifugal force in radial counterflow. The heavier constituents including soot, CO2, NO2and VOCs pass out of the periphery of the disks and into a shrouding tank from which they may be separately extracted. The lighter constituents including the nitrogen ballast, oxygen, water vapor and NO form a sink flow radially inward toward the axis a—a and out of the workspace and through the axial extraction port8.

The heavy constituents impinge a shrouding tank wall9disposed about the periphery of the disks. Backpressure from vortex impingement on the shrouding wall assists the inward sink flow through the shear layer. In contrast to prior art mufflers, backpressure does not go back into the axial feed port but instead it goes over the baffle into the axial extraction port8. So the backpressure problem of the conventional static muffler is avoided by the open von Karman geometry, and noise is abated. The exhaust gas is expanded and made to do work, so it loses enthalpy and the acoustic pulses are dissipated.

FIG. 2shows a cascade of several disks, plus other elements. An exhaust gas input stream1enters through an axial feed port2in a rotatable axial feed conduit10which forms a lower disk5. All of the disks above this lower disk it are linked together by vanes6so all of the disks of the cascade are co-rotatable in the direction shown by the arrow11. That includes the upper disk for this stage and for the successive stages. A baffle3disposed between the upper and lower disks of each stage is attached to a drive spindle13and not to either of the disks. The drive spindle is connected to a motor14. The baffle of each stage separates its axial feed port2and the axial extraction port8. The baffle rotation direction12is opposite to the direction11of the rotation of the disks.

The motor14also rotates the vanes on a blower which assists exhaust of nitrogen ballast out of the shrouding tank at19. The motor may be an electric motor, a device connected to the engine, or a device actuated by slip stream over a vehicle. Assisted exhaust reduces backpressure and increases fuel efficiency of the internal combustion engine.

The advection caused by the motor-driven baffles and their vanes6aextending into the workspace4of each of the stages drives the disks in counter-rotation by means of peripheral vanes6connecting the disks of the stages.

The heavier products that accumulate at the periphery of the counter-rotating baffles and disks are stored in a receptacle such as the soot hopper15and the CO2outlet in the shrouding tank which leads to tanks and compressors suitable for storing gases.

After the exhaust stream has been stripped of its heavier constituents, the remaining NO and other gases such as CO and CO2 can be cracked by electrolysis at a stage in the cascade. In this stage, a conductive disk16, here also attached to the drive shaft13, is rotated through the transverse magnetic field of at least one magnet17to form create a Faraday disk, or disk dynamo, having opposite radial currents making the edge of the disk a cathode18and the center of the disk an anode. As the NO, CO, and residual CO2passes over this cathode, both above and below the spinning disk, the molecules dissociate. Harmless N2and O2flow out at19while elemental carbon deposits on the cathode.

Any residual soot then accumulates at the central anode end of the disk. The anode charge may be used to attract soot to the inlet screen of the soot hopper15as in conventional electrostatic precipitators. and this charge can also be used to charge the inlet screen of the soot hopper15as an anode.

The light fractions, including the nitrogen ballast, then pass though the central outlet port19of the shrouding tank. Slipstream over a muffler mounted on a moving vehicle will also maintain low pressure by the Venturi effect in the outlet of the shrouding tank19. The result is a safe atmospheric outlet stream20of N2,O2and water vapor that is released to the atmosphere, without noise.

Under certain conditions, such as long-haul trucking, the slipstream may assist exhaust so much that mass flow through the muffler is sufficient to allow the motor to be used as a generator. In that case, the baffles will be driven by instead of driving the mass flow through the muffler, such that the drive shaft turns a generator. Suitable means for switching the motor14to generator mode are available for that possibility.

FIG. 3shows a cross section of the left half of a single pair of counter-rotating disks featuring more detailed capture of the heavier constituents. The exhaust gas input stream21enters through an intake vent22. The intake flow is partially blocked by a baffle23and passes through vanes56. These vanes either act as turbines to extract mechanical energy from the flow to use for increased disk rotation, or act as impellers, to increase the flow, if the disk rotation is driven by a motor The intake flow then passes into a workspace24located between the lower disk25, which contains an opening26for the intake vent22, and the upper disk27which contains an opening28for an axial outlet vent29for the axial outlet stream30. The two disks turn in opposite directions, as indicated by31for the motion of the top disk and32for the motion of the lower disk.

An net positive pressure in the input stream21can be the result of the positive pressure created by the engine, and it can be enhanced by an input pump, such as the inlet screw pump33incorporated into the intake vent22, and which turns from the motion32of the spinning lower disk25. Similarly, a net negative pressure in the axial outlet stream30can be created by an axial outlet pump, such as the outlet screw pump34incorporated into the axial outlet vent29, which turns from the motion31of the spinning upper disk27. The inlet screw pump33and the outlet screw pump34serve to assist flow of exhaust out of the engine for improved fuel efficiency. Because the disks are turning in opposite directions, the slope or “handedness” of the screws must be opposite as well, in order to maintain the same upward flow.

In the workspace24between the counter-rotating disks25and27, radial counterflow turbulence with a branching network of fine vortices in the shear layer separating the lighter constituents35, such as oxygen, nitrogen, and water vapor, from the heavier constituents36in the exhaust stream, such as soot, NOx, VOCs and carbon dioxide. The lighter constituents35such as nitrogen and water vapor are drawn inward through the vortex cores into the axial outlet stream30near the axis of rotation37, and the heavier fractions36churn in the workspace24until they eventually migrate outward to the periphery38of the disks.

For particulates such as soot, an angled annular deflector wall39built into the lower disk25could direct the stream downward, while at the same time inducing cross-turbulence with embedded vanes in the deflector wall40. The heavier particulates such as soot, because of their weight and inertia, are left behind and fall downward through an opening in the disk44into a static annular soot collection pipe43which connects to a descending vertical soot collection pipe44. At the same time, the heavier gaseous components46continue onward and drift upward to a gas opening47, and beyond that to a static annular gas collection pipe48which connects to a descending vertical gas collection pipe49.

The collection of the soot is preferably enhanced by an electrostatic charge applied to the soot outlet pipe42. This electrostatic charge can be generated by triboelectric charging means. For example, the static annular soot outlet pipe42can be made of polyvinyl chloride (PVC), and a charging element, such as a leather or rabbit fur pad50attached to the moving disk rubs against the annular soot outlet pipe42to charge it. This charge is regulated by a periodic connection to ground.

The disks can be turned by the action of the flow against turbine vanes, by a motor such as one connected to the central shaft58, or by an air stream. Here vanes attached to the outer casing51and to the upper disk25rotate the disk using the air stream passing by a moving vehicle. One example of a turbine for capturing the wind is this design based on a Pelton wheel. The forward-facing open scoop-type vane is at52. Both the forward-facing open scoop vane52and the backward-facing closed vane53are shown inFIG. 6as coupled by a link51ato the upper disk27in order to turn it. The counter-rotation of the lower disk27is caused here by inter-disk gears54between the disks, engaging a gear tooth track in the upper disk25and a gear tooth rack55on the baffle23with its vanes56underneath which couple the baffle to the lower disk. The gears have bearings coupled to a rigid shaft57coupled to the central support shaft58. This central shaft supports the rigid cylindrical support structures containing the central axial intake port22for the lower disk and the central exhaust port29for the upper disk, as well as the low-friction thrust and roller bearings and centering support structures for the lower disk at59and for the upper disk at60, which allow the disks to rotate freely. The baffle also has a bearing and is centered on this central shaft, and the baffle is linked by the vane56to the lower disk so they rotate together.

FIG. 4shows another cross section of the left half of a single pair of counter-rotating disks shown inFIG. 3, with indications of the locations of the four horizontal cross section planes shown in composite inFIG. 5. The cross section plane A below the lower disk is at61, the cross section plane B above the lower disk is at62, the cross section plane C below the upper disk is at63, and the cross section plane D above the upper disk is at64.

FIG. 5shows a composite of the four cross sectional planes indicated inFIG. 4, starting in the lower left and going clockwise, with the view looking downward in each case. The cross section plane A below the lower disk shows the annular soot collection pipe43which connects to a descending vertical soot collection pipe44. The outer casing51is coupled to multiple vanes which in their open scoop position52can capture the energy of a passing airstream from the motion of a vehicle65to induce a rotary motion in the casing and to any disks coupled to it.

The cross section plane B above the lower disk25shows the axial intake port26and the lower disk25, with its rotary motion32, its periphery38, the soot collection slot42, and the vanes connecting the lower disk23to the baffle23. Both the slots in the upper and lower disks are not continuous, but have periodic interruptions to maintain the structural integrity of the disk.

The cross section plane C below the upper disk, again looking down, shows the upper surface of the lower disk25and its rotary motion32, and its periphery38. The baffle23has a gear tooth track55for at least one inter-disk gear54, which has a shaft coupled to the rigid central support shaft58. Outside of the periphery are the alternating vertical pipes for the collection of soot44and of heavy gases49. The counterflow turbulence between the disks features vortices separating the components, where the lighter constituents35go inward and the heavier constituents36go outward.

The cross section plane D above the upper disk27shows its rotary motion31, which is the opposite of the rotary motion of the lower disk32. The heavier gases collection slot47is shown underneath the static annular peripheral gases collection pipe48which leads to the vertical gas collection pipe49. The closed shield orientation of the vanes in the outer casing is shown at53, along with the induced motion of the vanes66caused by the passing airstream from the motion of a vehicle65; the effect of the airstream on the vanes can be increased with a windshield67which favors the engagement with the vanes in their open scoop position52. For a stack of disks such as that shown inFIG. 6andFIG. 7, other gears between the upper and lower disks would transmit the motion of one disk in counter-rotation to the next. This is shown here with an outer gear68which engages an outer gear track69on the upper surface of the upper disk, and has a corresponding gear track on the underside of the lower disk. This outer gear68is attached by a shaft70to the static centering support structure for the upper disk at60.

FIG. 6shows a cross section of a cascade of disks, and an example of the path71that the exhaust gas, and the sound vibrations that it contains, travels through them. As the pressure waves of various frequencies caused by the engine travel through repeated regions of extreme turbulence, they lose their coherence and strength, and thus the exhaust stream becomes quieter.

The stack of counter-rotation disks can be driven by a motor, or be passively driven by the passing wind motion in turbine vanes. Here a large scoop vane52is shown along with its corresponding shield vane53in a rotated position. Both are coupled to a rotating casing51. Through the casing, the scoop vane's energy is coupled through a connection72between the casing and the topmost disk27. From there, the energy is transmitted in turn downward through successive disks in the stack through inter-disk gears such as at54, and outer gears such as at68, engaging gear racks inside55and outside69of the workspace24. The energy from the pressure of the exhaust stream is also translated into rotary motion through the passage of the stream through the screw pumps such as34, which also act as turbines to turn the disks. Thus, the speed of rotation of the disks can be determined by how fast the engine is running or how quickly the vehicle is moving.

The soot collected toward the periphery38of each of the stacks of disks is channeled into a descending network of pipes. It first goes into an annular static soot collection pipe43and outward in a radial soot collection pipe to a vertical soot collection pipe44, collected into a main pipe leading to a soot compression chamber73where it can be compacted for storage into small brick-like soot chunks74. This compaction can be aided by a motor75driving a screw conveyor76. Because of the combustible carbon, which may include nanotubes, and the unburned fuel in the compressed soot, these compressed soot chunks can have commercial value, which justifies the business activity of collecting them at gas stations.

Similarly, the peripheral gases, including carbon dioxide, are collected by a network of pipes, beginning with a static annular collection pipe48leading to descending collection pipe49. The final collection can be aided by a gas pump78between the main collection pipe79and the storage tank80.

The cascade of successive processing shown here will progressively clean the outlet gas stream through stage after stage, until what is released at the top is significantly less polluted than the original gas stream.

FIG. 7shows an alternate design with a cross section of a cascade of disks featuring a combined peripheral capture of soot and CO2within an enclosing shrouding tank, and where the disks are turned by the pressure of the exhaust stream on vanes on the disks, optionally assisted by a motor14attached to a central shaft. The path of the exhaust stream is shown at71. The main driving vanes81are underneath the baffle23and connect it to the lower disk, and other shallow vanes are in the surfaces of the disks, and on the top surface of the baffle. The vane on the lower disk is at82, and the vane on the upper disk is at83. The vanes also extend out toward the periphery38. The pattern of the vanes is shown inFIG. 8. An example vortex in the workspace is shown at84. More detail about the radial counterflow in the workspace is shown inFIG. 9. The internal exhaust gas pressure with optional assistance from the motor turns the disks in counter-rotation, thereby also evening out the pulses and leading to exhaust pulse scavenging. The motion from the vanes is also transferred in counter-rotation through outer gears68engaging outer gear tracks on the outer surfaces of the disks, with the gear shaft70anchored to the axial static support and bearing60. The rotation of this gear transmits the motion of an upper disk27to cause the counter-rotating motion of the lower disk25in the opposite direction. These opposite directions are shown at31and32. The disks have a peripheral gap85which allows for the escape of soot and CO2which is contained in the interior88of an enclosing tank87. The bottom of the tank can contain the soot hopper15and the outlets for captured gases. A peripheral shield86prevents the soot from clogging the gear68, and the small gap at the periphery can be kept clear of accumulated soot by an intermittent element such as a piece of nylon attached to the edges of one disks sweeping the gap clear.

FIG. 8shows a top view of the scissoring vanes from both upper and lower disks superimposed. The disks25,27are shown in superposition, with the heavier lines such as at83representing the vanes on the lower disk, whose motion is shown at32, and the lighter lines such as at84representing the vanes on the opposing upper disk, whose motion is shown at31. Each disk comprises an array of radial vanes curving away from its direction of rotation, such that rotation advects the exhaust gas stream and heavier components radially outward by both disks simultaneously. In superposition, the radial vanes83,84on the disks intersect at shearing points which are in close opposition but not in contact with each other. These shearing points move out along radial lines (indicated by the dashed lines) as the disks counter-rotate. These lines of high shear sustain the sink flow of the lighter product stream by refreshing the radial vortices, and the periodic shear pulses cause peristaltic pumping of sink flow through the vortex cores. The vortex-wall interaction as swirl collapses where the disks pinch together at the periphery38converts the radial vortices generated by the shearing disks into axial jets driving a recirculation flow radially inward toward the axis of rotation. See Shtern and Hussain, “Collapse, Symmetry Breaking, and Hysteresis in Swirling Flows,”Ann. Rev. Fluid Mech.31:537-66 (1999), particularlyFIG. 1thereof.

FIG. 9shows a schematic view of radial counterflow in the workspace24between the disks. Laminar boundary layers, where the momentum diffusion from the disks25,27into the exhaust stream occurs, set up against the disks. Radially outward flow of the exhaust stream and the heavier product is forced by momentum diffusion in the boundary layers. A shear layer sets up between the counter-rotating laminar boundary layers. The shear layer comprises radial vortices which act as a sink flow network, into which the lighter gas product stream concentrates and proceeds in sink flow to the axial extraction port28which provides a path for the scrubbed exhaust stream out of the workspace, leaving soot, CO2, and NOx behind in a collection tank.

Area-preserving fractal flow networks, such as the root system of trees, are Nature's way of organizing flow with a minimum of pressure drop, in a multi-scale path of least resistance. The open von Karman geometry of the present disclosure allows a fractal flow network in the shear layer. One radial vortex axis is shown as a dashed line91. Low density fractions in the workspace24, such as oxygen, nitrogen, and water vapor, concentrate in the shear layer, and soot and CO2 are expelled by centrifugation out of the shear layer and into the boundary layers. The arrows show the magnitude and direction of radial flows at various distances from the disks, with respect to the axis91in the workspace24.

FIG. 10shows a cross section of a cascade of disks where an early release of the exhaust stream into the environment can be made if the stream has been sufficiently cleaned or reduced in noise. If the successive stages have produced an acceptable outlet after only a part of the stages have been used, a valve can be thrown and the outlet from the acceptable stage immediately released into the environment.

The vanes have been omitted from the representation for clarity. The central stack of disks are linked to a central shaft, and are turned together by a motor or other motive force. All of these components turning in the same direction have a hatched fill. The interspersed disks are linked together at their periphery in a rotating drum92with holes to allow for the escape of the heavy constituents. Planetary gears93drive the two assemblies in counter-rotation. Alternatively, only the central stack could move, and the others would be static.

The processing can be considered as being divided into four zones, rising from bottom to top. Escape valves94allow for the gases to exit the processor early, if they have been sufficiently cleaned.

The materials used for the stack of disks will likely vary according to their height in the stack. For instance, in the lowermost disks, where hot and corrosive gases are coming from the engine, resistant materials such as ceramics or specially coated metal can be used. For the disks in the highest parts of the stack, the temperature and corrosiveness of the gases is much lower, and sound muffling is more important, so flexible disks or disks made of energy-absorbing materials can be used to absorb vibrations, or mesh disks with soft coatings that are periodically replaced as part of oil change services. Particulates such as metals may adhere to the coatings.

FIG. 11shows an example of the charging of the disks for cracking the component gases. In this case, the inner disks linked to a central shaft are all charged as anodes95, and the interspersed disks are charged as cathodes96. The electrical potential transferred into the workspace would be used to crack gases and molecules into their constituents.

This design can be used to treat many kinds of exhaust gas streams, including those from static engines, ships, and trains. Therefore, the scope of this disclosure should not be considered to be limited to the exemplary description herein.