Pollution Control Device

Abstract

Method and means for regulating the pollutants discharged from an internal combustion engine by regulating the flow of a portion of the exhaust gases from the exhaust manifold to the intake manifold by controlling a reed valve to precisely meter the flow of exhaust gases and/or ambient air in response to atmospheric pressure, intake manifold pressure and exhaust manifold pressure.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an improved pollution control device designed to utilize exhaust gas recirculation in an internal combustion engine as the means for reducing carbon monoxide, hydrocarbons and oxides of nitrogen.

The ecology movement has made people more aware of air borne pollutants of all types. There has been considerable activity recently in attempting to reduce the level of pollutants discharged from an internal combustion engine as used commonly in vehicles. The increased quantity of pollutants passing into the atmosphere as a result of the increased use of vehicles having internal combustion engines has caused concern with respect to the health and well-being of human beings as well as other living organisms. One method proposed for reducing the pollutants discharged from an internal combustion engine was to seal the system and return a portion of the exhaust gases mixed with gases from the crank case to the intake manifold. An example of a patent illustrating such means is MacMahon U.S. Pat. No. 3,362,386. The MacMahon arrangement is relatively complex and undesirably reduces the exhaust gas temperatures before returning it mixed with crank case gases to the intake manifold.

Another arrangement for reducing the pollutants discharged from an internal combustion engine is shown in Cornelius U.S. Pat. No. 2,722,927. The Cornelius system introduces exhaust gases to the combustion chamber of an internal combustion engine to dampen out the surges normally resulting from the rapid opening and closing of the intake and exhaust valves. Exhaust gases are introduced only when required in order to effect maximum volumetric efficiency and at all other times the gases will pass out of the exhaust pipe. This system is rather complex for it utilizes governors, diaphragms and associated linkages and does not effectively control the discharge of pollutants during all operating conditions of the internal combustion engine.

It has also been suggested that catalytic converters be employed in mufflers to help break down the pollutants before they are discharged to the atmosphere. The pollutants are still found in the engine and in the event of malfunction would be discharged to the atmosphere. Further such systems are relatively expensive.

An object of the present invention is to provide an improved pollution control device for reducing the formation of pollutants formed within the internal combustion engine by achieving a better combustion process.

Another object of the present invention is to provide an improved pollution control device wherein the formation of nitrogen oxide pollutants in an internal combustion engine is reduced.

Still another object of the present invention is the provision of an improved pollution control device which reduces the production of hydrocarbons, carbon monoxide and nitrogen oxide in an internal combustion engine, without increasing the formation of aldehydes or hydrocarbon reactivity.

These and other objects and advantages of the present invention will be made more apparent hereinafter.

DESCRIPTION OF THE DRAWING

There is illustrated in the attached drawing a presently preferred embodiment of the present invention wherein like numerals in the various views refer to like elements and wherein:

FIG. 1 is a perspective view of an internal combustion engine embodying the pollution control device of the present invention;

FIG. 2 is a perspective view of the pollution control device of the present invention;

FIG. 3 is a cross-sectional view of the exhaust recirculation plate taken generally along the line 3--3 of FIG. 2;

FIG. 4 is a bottom view of the induction plate taken generally along the line 4--4 of FIG. 2;

FIG. 5 is a cross-sectional view of the induction plate taken generally along the line 5--5 of FIG. 4;

FIG. 6 is a cross-sectional view illustrating the connection of the conduit to the induction plate, taken generally along the line 6--6 of FIG. 2; and

FIG. 7 is a plan view of a reed valve for regulating the admission of fresh air into the exhaust recirculation plate.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Referring to FIG. 1 there is illustrated an internal combustion engine 10 with which the pollution control device 12 of the present invention may be associated. The engine 10 is of conventional design and comprises a block 14 having a pan 16 secured to the bottom thereof which cooperates to define a crank case chamber. The usual pistons and cylinders are confined within the cylinder block 14 which is closed at the top by a cylinder head and valve cover 18.

Attached to the engine 10 is an intake manifold 20 that is operatively associated with the carburetor 22 and the usual air cleaner 24. Also associated with the engine 10 is an exhaust manifold 28 which includes a conduit 30 adapted to communicate exhaust gases from the engine to a muffler (not shown) from which the gases may be discharged through a tailpipe to the atmosphere. As will be apparent to those skilled in art, the intake and exhaust manifolds may be connected to the cylinder block or to the cylinder head.

The internal combustion engine 10 includes a distributor mechanism 32 that is adapted to be connected by means of electrical conduit to the spark plugs affixed to each cylinders. The engine 10 is provided with a generator or alternator 34 operatively connected to the damper pulley 36 by means of belt means 38. The belt means 38 is also connected to the pulley 37 for the fan 39 so as to drive the fan 39 and thereby pass the air over the radiator to help cool same.

It has been found that the reduction of oxides of nitrogen, carbon monoxide and hydrocarbons emitted from an internal combustion engine may be accomplished by recirculating a portion of the exhaust gases from the engine 10 via the pollution control device 12 which is disposed between the exhaust manifold 28 and the intake manifold 20, such control device also being the metering means, all being responsive to the differential pressure between the intake manifold pressure, exhaust manifold pressure and ambient air pressure.

Turning now to FIG. 2 there is better illustrated the pollution control device 12. The exhaust recirculating plate 40 is disposed between the exhaust manifold 28 and the conduit or exhaust header pipe 30. The exhaust recirculating plate 40 communicates with the induction plate 42 disposed in the intake manifold between the intake manifold 20 and the carburetor 22 by means of a conduit or tube 44. Each of the plates 40 and 42 is provided with holes 46 and 45 which are adapted to be aligned with holes in the flanges on the respective manifold pipes, with which they are joined so that fastening means, for example, bolts may pass through the aligned holes to secure the plates 40 and 42 respectively in fluid tight relationship with the exhaust manifold 28 and the intake manifold 20 respectively.

A portion of the exhaust gases enter passages 48 in the exhaust recirculating plate 40 and pass through the longitudinal passages 48 to a chamber 49 (FIG. 3) at one end of the exhaust recirculating plate 40. These exhaust gases then pass upwardly through the tube 44 to the induction plate 42 under the carburetor 22. The induction plate 42 has a plurality of passages 52 therein cooperating with the inlet chamber 54 for guiding the exhaust gases from tube 44 through the ports 52 to the annular chamber or groove 58 defined within the induction plate 42. The inner wall of the induction plate 42 defining the opening 62 in the induction plate 42 is provided with a plurality of slot 60 leading from the groove 58 into the throat or opening 62 of the induction plate. The exhaust gases entering the groove or chamber 58 are ducted via the groove 58 and the slots 60 into the throat area 62 at an angle causing them to swirl while entering the intake manifold directly under the carburetor 22. These exhaust gases being hot and swelling help vaporize the fuel drawn through the idling circuit. By heating the fuel coming from the idling circuit, it is possible to lean down the idle fuel-air ratio so as to materially reduce the carbon monoxide pollutants, for example in one test, from 3.5 to 1 percent at idle.

In addition, there is provided in the pollution control device within the chamber 49 of the exhaust recirculation plate 40, a reed valve 70 that is adapted to cooperate with fresh air inlet openings 72 so as to selectively permit the entry of fresh air into either or both the exhaust manifold 28 and the intake manifold 20. The chamber 49 is defined by a recess within the exhaust recirculation plate 40 and a separate plate member 69 adapted to be secured to the exhaust recirculation plate by suitable fastening means, for example screws 71. The reed valve 70 has two holes 70a therein receiving guide pins 74 for guiding the up and down movement of the reed valve 70 as viewed in FIG. 3 toward and away from the inlet ports or inlet openings 72. In addition, a metering orifice 70b is provided in the reed valve 70 to permit a predetermined flow of gas through conduit 44 even if the reed valve 70 is closing off the inlet to conduit 44. The area of metering orifice 70b is determined by the displacement of the engine.

The reed valve 70 allows fresh air to be drawn into the system through the inlet openings 72 in the plate 69 during idling, low cruise, and deceleration modes of engine operation. During idle, deceleration and at cruise speeds, there are negative pulsating pressures in the exhaust manifold 28. During the idle mode of engine operation, the reed valve 70 allows fresh air to enter the holes 72 and the chamber 49 and mix with warm exhaust gases recirculated through the metering orifice 70b in reed valve 70 to the induction plate 42 under the carburetor, thus eliminating rough idling, which would otherwise be present with the leaner air-fuel mixture.

Recirculation is only necessary during idle or deceleration to reduce carbon monoxide and hydrocarbons as oxides of nitrogen are low during these modes of engine operation. The carbon monoxides are reduced during acceleration and cruise modes of operation by the exhaust gases entering the induction plate 42, heating and further vaporizing the fuel where more complete combustion is possible. It is apparent that when the idling mixture is leaned down, it will tend to lean the mixture down during cruise or any speed where the carburetor throttle butterfly valve is between closed and one-fourth open. This is due to the fact that the fuel flow through the idling circuit is realized up to one-fourth of the throotle opening. In general, by reducing the fuel-air ration during cruise, bucking or uneven operation results. This problem is eliminated by the hot gases recirculating into the induction plate 42 under the carburetor, heating the incoming fuel-air mixture and thus giving a homogeneous mixture which will completely combust in the cylinders of the engine 10.

When the engine 10 is decelerating from high speeds, the high intake manifold vacuum encourages dilution and over-richness of the incoming charge of fuel and air with the exhaust gases drawn back into the cylinger before the exhaust valves are fully closed. This causes incomplete combustion in the deceleration mode resulting in high emissions of pollutants, particularly hydrocarbons. In the present invention, the reed valve 70 is open due to the high vacuum in the intake manifold 20. Fresh air is allowed to enter the exhaust recirculation plate 40 and through the metering orifice 70b in reed valve 70 the induction plate 42 to the intake manifold, thus providing some additional air for combustion and also reducing the vacuum on the idling circuit, which in turn reduces the fuel flow through the idling circuit. The reed valve 70 also allows fresh air to enter the exhaust manifold where there is a vacuum due to pumping action during deceleration. This also reduces the vacuum on the idling circuit which reduces over-rich mixture, thus insuring combustion and reducing the emissions of carbon monoxide and hydrocarbons during the deceleration mode of engine operation.

When the engine is accelerated, the exhaust manifold pressure closes the reed valve 70 against the ports 72, which allows a larger volume of exhaust gases to recirculated to the induction plate 42, thus diluting the intake charge and causing a reduction of oxides of nitrogen. A slight overall reduction of power which might be expected due to the reduction of volumetric efficiency is not experienced, since the introduction of exhaust gas recirculation slows the combustion process within the cylinders, allowing for more complete utilization of fuel on each power stroke. Acceleration performance is substantially improved. Fuel consumption will be reduced due to the leaner mixture and better atomization of the fuel-air inlet charge will result.

Considering FIGS. 4 and 5, there is better shown the detail of the plurality of slots 60 in the inner wall forming groove 58 of the induction plate 42. The slots 60 which lead from the groove 58 to the throat 62 of the induction plate are designed to create a high frequency sound wave when the exhaust gases reach high velocity during acceleration and high speed cruise operation of the engine. The high frequency, high energy sonic standing waves cause the fuel-air mixture to disperse in a homogenous fashion therefore creating an optimum burning condition in the cylinders.

An inlet fitting 80 is provided in the wall of the induction plate 42. The hole or passage through the fitting 80 is closed by a screw 82 that may be selectively removed, for example every two thousand miles, to permit a high pressure air supply to be affixed to the end of fitting 80 so as to force high pressure air through the induction plate 42 to remove excess carbon build up in the groove 58 and the slots 60. High pressure air will also be forced down the tube 44 through the groove 58 as to clean excess carbon formed in the tube 44, the holes 48 and the reed valve 70. This desirably eliminates the necessity to remove the induction plate 42 and exhaust recirculating plate 40 from the manifold pipes for cleaning.

Turning again to FIG. 2, it is noted that the exhaust recirculation plate 40 includes a hydrocarbon separator 84. The hydrocarbon separator 84 comprises a generally cylindrical perforated member having flared fingers or projections 85, 86 extending outwardly from each end thereof. A plurality of retainer arms 87 connected at one end to the separator 84 and at the other end to the exhaust recirculating plate 40 maintain the hydrocarbon separator within the opening 62 in the exhaust recirculation plate and in the exhaust manifold 28. The hydrocarbon separator 84 is disposed in the exhaust manifold 28 so as to come into contact with the exhaust gases at a very high temperature of the gases. During operation, the hydrocarbon separator 84 will become red hot and during acceleration and high speed cruise there will be separation of the hydrogen and carbon atoms, thereby helping them to oxidize and assist in minimization of pollutants at the source. The fingers 85, 86 extending outwardly from the main body of the hydrocarbon separator 84 cause turbulence in the exhaust gases as they flow from the exhaust manifold 28 to assist the breakdown and separation of hydrogen and carbon from the exhaust gas.

There has been provided by the present invention an improved pollution control device utilizing exhaust gas recirculation as a means of reducing the oxides of nitrogen, carbon monoxide, and hydrocarbons formed in the operation of the internal combustion engine. By the present invention, a portion of the exhaust gased and/or ambient air recirculation flow are precisely metered in automatic self-response to atmospheric or ambient pressure, intake manifold pressure, and exhaust manifold pressure.

As an example of the improvement through use of the present invention, comparative tests were made with and without the present improved pollution control device. The results utilizing a 1965 Plymouth without the pollution control device are shown on Chart I below and the results on the same vehicle utilizing the improved pollution control device of this invention are shown in Chart II below. The 1965 Plymouth had a standard or stick transmission, and a 225 CID engine. The testing followed the Federal Standards for a 7-mode hot cycle test program.

CHART I __________________________________________________________________________ Mode Idle 0-25 30C 30-15 15C 15.30 50-20 __________________________________________________________________________ CO.sub.2 % 6 12.25 12.55 12.40 7.47 14.37 13.33 6.32 CO,% 6 3.12 2.33 4.01 3.85 0.39 2.12 2.93 HC,PPM 6 235 308 294 2500 412 360 3600 (HEX) NO,PPM 6 115 1255 821 325 839 1079 309 NO.sub.2, PPM 6 N/R W.F. 0.042 0.244 0.118 0.062 0.050 0.455 0.029 __________________________________________________________________________

CHART II __________________________________________________________________________ CO.sub.2 % 6 9.77 11.83 13.66 10.78 11.42 12.86 7.64 CO, % 6 0.09 0.98 1.33 1.62 0.12 0.91 1.12 HC, PPM 6 720 488 250 465 250 242 1605 (HEX) NO,PPM 6 86 768 387 144 233 751 144 NO.sub.2,PPM 6 N/R W.F. 0.042 0.224 0.118 0.062 0.050 0.455 0.029 __________________________________________________________________________

Calculating the concentration emissions as presented in Charts I and II, the CO was reduced from 2.54 to 1.05 percent. The hydrocarbons (hexanes) were reduced from 618 ppm to 445 ppm. The NO was reduced from 974 ppm to 658 ppm. It is apparent from the foregoing, that the novel pollution control device, incorporating an exhaust gas recirculating valve with plate or reed valve means, was effective in reducing undesirable pollutants formed within the internal combustion engine.

While presently preferred embodiments of the invention are shown in relation to a four-cycle internal combustion engine with carburetor(s) fueled by gasoline, it will be apparent to those skilled in the art, that the invention can be applied to both internal and external combustion engine powered with liquid or gaseous fossil fuel, as well as engines equipped with fuel injectors and/or superchargers, diesel engines, rotary engines and all such embodiments as applied to two-cycle engines.

While I have described a presently preferred embodiment of the invention, it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

Claims

1. In an internal combustion engine that utilizes the compressing of a fuel-air mixture, such engine comprising an exhaust manifold means and an intake manifold means, the improvement comprising control means for regulating the flow of a portion of the exhaust gases from the exhaust manifold means to the intake manifold means, said control means including an exhaust recirculating plate means in the exhaust manifold means, a passage communicating to the intake manifold means and a passage communicating to atmosphere, valve means in said exhaust recirculating plate means to meter the exhaust gas and/or ambient air recirculation flow in automatic self-response to the differential pressure of atmospheric pressure, intake manifold pressure and exhaust manifold pressure, so as to reduce the formation of oxides of nitrogen formed within the internal combustion engine, the flow of exhaust gases from the exhaust manifold means to the intake manifold means being controlled by the valve means which comprise a plate valve in the exhaust recirculating plate means which is operative responsive to the differential of intake manifold pressure, exhaust manifold pressure, and atmospheric pressure, for admitting fresh air into the exhaust recirculating plate means during idling, low cruise and deceleration and to precisely meter the flow of exhaust gases back to the intake manifold in all modes of engine

2. the structure as in claim 1 wherein the internal combustion engine includes a carburetor and an induction plate between the intake manifold

3. The structure of claim 2 wherein conduit means connect the exhaust

4. A structure as in claim 3 including a hydrocarbon separator associated with the exhaust recirculating plate means and disposed in the exhaust manifold means for helping to separate and oxidize hydrogen and carbon atoms in the exhaust gas, said hydrocarbon separator comprising a body member with flared fingers disposed in the exhaust manifold means for

5. The structure as in claim 1 wherein a fitting is provided in the wall of the induction plate means, said fitting being adapted to communicate with a source of pressurized fluid so as to permit pressurized fluid to be introduced into the induction plate means for removing excess carbon

6. The structure as in claim 1 wherein the plate valve has a metering orifice therein.