Polluting Fume Abatement Apparatus

Abstract

Fume abatement apparatus comprises, in combination, A. an exhaust duct for passing a stream of engine products of combustion having electrically chargeable content, and B. means including an ion generator to effect a flow of ions into said stream, with ion density and polarity to so change the electrical charge of said content as to enhance subsequent precipitation thereof on a surface.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to pollution control, and more particularly concerns engine exhaust fume abatement.

At the present time a great deal of effort is being directed to the control of atmospheric pollution. In urban areas such pollution in large part is caused by vehicle engine exhaust discharges, and as a result there have been many devices proposed as partial solutions to the problem; however, to our knowledge, insufficient attention has been given to the reduction of engine exhaust particulate pollution by methods involving electrostatics. Particularly, apparatus and methods involving modes of operation characterized by the present invention have not been forthcoming. In this regard, recent tests show that automobiles with attached conventional devices for controlling smog can produce around 200 billion submicron particles per cubic foot of exhaust, compared with about 100 billion such particles for old cars without such devices.

SUMMARY OF THE INVENTION

It is a major object of the invention to provide internal combustion engine exhaust fume abatement apparatus comprising an exhaust duct for passing a stream of engine products of combustion having electrically chargeable content; and, means including an ion generator operating to effect a flow of ions into the stream, with ion density and polarity to so change the electrical charge of such content as to enhance subsequent precipitation on a surface. As will be seen, the generator may typically comprise multiple pointed tips proximate the duct, and a high voltage supply connected with the tips.

In one form of the invention, the tips may be exposed to the exhaust stream, and in another form an insulative shroud may protect the tips from direct exposure to the growing exhaust, the shroud defining an outlet for ions to pass from the tips to the stream path. As to the latter, means may be provided to pass auxiliary gas such as air to the tips to travel with the ions into the stream.

Further, the duct downstream of the locus of ion flow into the stream may advantageously have an insulative inner surface exposed to the stream; the duct may comprise an exhaust pipe or stack extending horizontally or vertically; and the duct may direct the ion treated exhaust at the ground for charged particle collection.

These and other objects and advantages of the invention, as well as details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which:

DRAWING DESCRIPTION

FIGS. 1-3 are vertical sections showing different forms of the invention.

DETAILED DESCRIPTION

In FIG. 1, an internal combustion engine, of Otto, Diesel, Wankel or other type, is indicated schematically at 10 as delivering exhaust at 11 to the horizontal tail pipe or duct 12. Such products of combustion may have electrically chargeable content such as submicron particles and larger hydrocarbon molecules, and tests indicate that there are in excess of 100 billion submicron particles per cubic foot of exhaust.

In accordance with the invention, an ion generator is provided to effect a flow of ions into the exhaust stream 14 in the pipe, with ion density and polarity to so change the electrical charge of the content as to enhance substantially the subsequent precipitation of the latter on a surface. In this regard, the extent of duct 80 downstream of the ion generator may have an electrically insulative inner surface or coating (ceramic, plastic or other) at 15 exposed to the charged stream, preventing neutralization of the ions and particulate charge during discharge flow of the exhaust from the generator to the duct outlet 16. The latter may be directed downwardly to discharge the content 14 toward and at the ground surface 17, where the particles become neutralized and collect, removed from the atmosphere.

The ion generator in FIG. 1 includes multiple pointed tips 18 proximate to, as for example, within the duct 12, and a high voltage supply 19 electrically connected with the tips. The latter may be defined by metallic needle 20 diverging in a downstream direction and in a cluster as shown, as is more particularly described in U. S. Pat. No. 3,308,344 to Harold Smith and George A. Korkos, A lead 21 connects the source with the needles via a mounting rod or needle 22 which may be carried by streamlined insulator body 23. Further, an insulative shroud may project at 24 in protective relation to the tips to prevent direct impingement of exhaust flow on the tips, the shroud defining an outlet at 26 for ions to pass at 27 from the tips into the exhaust stream. Body 23, and shroud 24 may consist of insulative (as for example plastic) material. Radial ribs 28 may support the body and shroud in the duct 80. Other types of shrouds, supports and ion emitting configurations may be employed so long as the referred to functions and modes of operation are realized. Duct 80 may be easily attached at 81 to pipe 12, and the latter carried at 83 by vehicle structure 84.

In FIG. 2, the engine 10a delivers exhaust to the duct 12 via a catalytic reactor 30 operating to change the molecular content of the flow to less noxious form. For example, CO may be oxidized to CO.sub.2, and NO dissociated to form N.sub.2 and O.sub.2 in the reactor. Particulate content emanating from the reactor is processed as described above and as to be described. The reactor 30 could alternatively be placed downstream of the ion generator.

The ion generator again includes multiple tips 31 to which high voltage, of selected polarity, is supplied. For example, over 5,000 volts DC negative may be employed, considering that the ground surface 17 to which the charged particles are to be attracted is normally positive. An insulative support for the needle cluster 31 as indicated at 33, and a shroud at 34.

Means is provided to pass auxiliary gas to the tips to travel with the ions 100 into the exhaust flow 35. Such means may include an air scoop or pump 36 outside the duct 80, and a line 37 to deliver the air to the ion generator, as for example to porting 38 in the support 33 opening to the region 39 in the shroud containing the needle cluster. Such air flow 101 tends to prevent exhaust backflow into the shroud, keeping the needles and tips clean and free of exhaust deposits.

In FIG. 3, exhaust from engine 40 is delivered at 41 to a vertical pipe or stack 42 as is found on trucks carrying Diesel engines. Ion generators 43, shrouded at 50, are carried by the stack wall and with spacing such as to direct positive ions 102 into the upward flow 44 of exhaust. A charged particle trap, as for example, a negatively charged grid or grids 45 is mounted downstream of the generators 43. The generators may produce positive ions to positively charge the particulate content of the exhaust, voltage supply being indicated at 46. Trap 45 may alternatively consist of steel wool or the like, and may be removable replacement, as facilitated by removal of stock upper section 42a. An insulative screen or liner 48 extends within the stack between the ion generator 43 and the grid or grids.

Claims

We claim:

1. Internal combustion engine exhaust fume abatement apparatus comprising, in combination,

a. an exhaust duct for passing a stream of engine products of combustion having electrically chargeable content,

b. means including an ion generator comprising multiple pointed tips to effect a flow of ions into said stream, with ion density and polarity to so change the electrical charge of said content as to enhance subsequent precipitation thereof on a surface,

c. an insulative shroud for said tips and exposed to said stream in an upstream direction, the shroud extending in protective relation to the tips to prevent direct impingement thereon of the engine products of combustion, and the shroud defining a downstream facing outlet for ions to pass from the tips to the stream path downstream of the tips, and

d. the duct having an electrically insulative lining extending from a region upstream of said shroud outlet and at the exterior thereof to a region proximate an outlet to the atmosphere defined by the duct to inhibit neutralization of said ions during their flow in the duct.

2. The combination of claim 1 including an internal combustion engine operatively connected with said duct to supply said stream thereto.

3. The combination of claim 1 wherein said means includes a high voltage supply electrically connected with said tips.

4. The combination of claim 1 wherein said tips are exposed to said stream in a downstream direction, only.

5. The combination of claim 1 where said shroud tapers in an upstream direction and extends in the duct to reduce the duct cross sectional area thereby effecting an increase in the stream velocity past the shroud and tips for mixing with the ions.

6. The combination of claim 5 including means to pass auxiliary gas to said tips to travel with the ions into the stream.

7. The combination of claim 1 wherein said ion generator includes a source of positive voltage in excess of +10,000 volts to effect positive ion flow into the stream.

8. The combination of claim 1 wherein said duct is defined by a vehicle tail pipe with said duct outlet directed toward the ground underlying the vehicle.