US3259117A - Method and apparatus for smog control - Google Patents

Description

July 5, 1966 J. M. RITCHIE 3,259,1 1 7 METHOD AND APPARATUS FOR SMOG CONTROL Filed July 8, 1964 INVENTOR. JEss M. PITCH/E ATTORNEYS United States Patent 3,259,117 METHOD AND APPARATUS FOR SMOG CONTROL Jess M. Ritchie, Oakland, Calif., assiguor to Fog-Aire,

{ Inc., Oakland, Calif., a corporation of California Filed July 8, 1964, Ser. No. 381,129 3 Claims. (Cl. 123-119) This invention relates generally to the reduction of air pollution, and is more particularly directed to a method of, and apparatus for reducing the concentration of unburned hydrocarbons in automobile exhaust gases.

The control of air pollution has become one of the major problems confronting large metropolitan areas. For the purpose of brevity in the following description, the term smog will be used hereinafter to denote the mixture of air pollutants generally present in the air of large urban communities. It is known that automobile exhaust gases constitute one of the major components of smog. In particular, the unburned hydrocarbons present in automobile exhaust gases are a major factor contributing to the respiratory irritation which is endemic in smog-filled areas. Unburned hydrocarbons in the exhaust are produced by incomplete combustion of the fuel mixture in the combustion chambers. This incomplete combustion, in turn, is caused by carbon deposits within the combustion chambers. During the operation of the engine, these carbon deposits are heated to incandescence, thereby causing pre-ignition of the fuel mixture. Therefore, the combustion of the fuel mixture does not proceed to completion, leading to the production of unburned hydrocarbons in the exhaust gas.

Various devices have been developed to reduce the concentration of unburned hydrocarbons existing in automobile exhaust gases due to the foregoing circumstances. One of the most common of these devices is the crankcase ventilator or so-called blow-by device. However, the conventional blow-by device possesses a relatively low scavenging efliciency, i.e., the reduction in the concentration of unburned hydrocarbons in the exhaust gas attainable with such a device is quite small. This is due to a conventional blow-by device being arranged to merely provide a re-cycling conduit which returns gases from the interior of the crankcase back into the combustion chambers of the engine. Thus, the operation of a conventional blow-by device has no efiect upon the actual source of unburned hydrocarbons, namely the formation of carbon deposits in the combustion chambers, and therefore the resulting reduction of the concentration of hydrocarbons in the exhaust gas is of relatively low order.

The present invention provides an improved method and apparatus for reducing the concentration of unburned hydrocarbons in automobile exhaust gases. Briefly, the method of the invention comprises passing crankcase gases through a water-filled scrubber, and injecting the eflluent gas from the scrubber back into the combustion chambers of the engine. The crankcase gas becomes saturated with water vapor when it passes through the water in the scrubber. When the saturated efiiuent vapor comes into contact with the incandescent carbon deposits in the combustion chambers, the water vapor combines with the hot carbon in the so-called water gas reaction. The prod ucts of the water gas reaction, chiefly carbon dioxide and carbon monoxide, are expelled from the combustion chambers into the exhaust manifold. In this manner, the meth- 0d of the present invention simultaneously ventilates the crankcase and removes carbon deposits from the engine combustion chambers. fuel mixture proceeds to completion, with a resulting marked decrease in the concentration of unburned hydrocarbons in the exhaust gases.

Accordingly, it is an object of the present invention to provide a method and apparatus for decreasing the con- Consequently, combustion of the Patented July 5, 1966 centration of unburned hydrocarbons in automobile exhaust gases.

Another object of this invention is to provide a method and apparatus for simultaneously ventilating the engine crankcase and introducing water vapor into the engine combustion chambers.

Yet another object of the invention is the removal of corrosive vapor, such as sulfuric acid, and particulate matter, such as ash, rust, lead sulfate, and the like, from the crankcase of an engine to thereby minimize the contamination of crankcase oil and reduce engine wear.

Still another object of this invention is to provide for improved fuel economy in the operation of an internal combustion engine.

A further object of the invention is the provision of a method and apparatus for simultaneously ventilating the crankcase of an internal combustion engine and simultaneously humidifying the air-fuel intake mixture introduced thereto wherein the humidification function is entirely selfregulating in accordance with the humidity of the atmosphere.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

FIGURE 1 is a schematic representation of the scrubber apparatus of the invention suitably connected to an automobile engine, and

FIGURE 2 is a detailed perspective view of the scrubber apparatus shown in FIGURE 1.

The method of the present invention, as noted previously, in basic respects comprises simultaneously ventilating the crankcase of an internal combustion engine by withdrawing blow-by gases therefrom, while humidifying the intake manifold of the engine. More explicitly, ventila tion of the crankcase and withdrawal of gases therefrom are preferably motivated by the intake vacuum of the engine. In this regard, a recycling flow path may he established between the crankcase and intake manifold of the engine whereby the pressure differential existing therebetween is in a direction to cause gas flow from the crank case towards the manifold. Saturation of the crankcase gases is best accomplished by first heating the gases to lower the relative humidity thereof and thereafter saturating the heated gases with water vapor by bubbling same through water en route to the intake manifold. Preferably heating of the gases is effected by passing the gases into heat exchange relation to the exhaust manifold of the engine, and in this regard the recycling flow path:

may extend in close proximity to the exhaust manifold.

Saturation of the relatively dry heated gases with water vapor may then be facilitated by providing a column of water in the flow path at a location between the exhaust manifold and intake manifold. For example, a scrubber bottle partially filled with water may be communicated at its lower end with the flow path at a point down-stream from the exhaust manifold, and at its upper end with the remainder of the flow'path extending to the intake manithe saturated gases combines with the hot carbon to proi duce carbon dioxide, carbon monoxide, and the like, which are expelled into the exhaust manifold. The carbon deposits are thus removed and pre-ignition of the intake fuel mixture is substantially eliminated. The fuel mixture is then able to burn to completion and the concentration of unburned hydrocarbons in the exhaust gases is manifestly reduced.

Considering now preferred apparatus for conducting the method described hereinbefore and referring to FIG- URE 1, there is shown a scrubber bottle 11 which is partially filled with Water 12 and is sealed by means of a cap 13. An intake conduit 14 extends downwardly into bottle 11 through cap 13, and terminates below the level of the water in a perforated loop 16. The other end of conduit 14 is wound around the engine exhaust manifold 17, and communicates with the interior of the engine crankcase by means of an opening in the valve cover 18. An exit conduit 19 communicates at one of its ends with the interior of bottle 11, and at its other end with the engine intake manifold 21. The crankcase breather tube 22 is sealed.

Referring now to FIGURE 2, there is shown a detailed view of scrubber bottle 11 and means for mounting it within the engine compartment. Cap 13 is integrally formed with a mounting bracket 23 which is attached to the engine firewall 24 by means of screws 26. A normally-closed check valve 27 is disposed in cover 13, and is positioned so as to open when the pressure inside bottle 11 exceeds the atmospheric pressure within the engine compartment.

In the operation of the apparatus shown in FIGURES 1 and 2, the downward movement of the engine pistons creates a vacuum within intake manifold 21. This vacuum is communicated to the interior of scrubber bottle 11 by means of conduit 19. Consequently, the interior of the engine crankcase is at a positive pressure relative to the interior of scrubber bottle 11. Blow-by gas inside the crankcase is thus forced out through opening 18 in the valve cover and enters conduit 14. In its passage through conduit 14, the blow-by gas is heated in that section of the conduit which is wound around the hot exhaust manifold 17. The relative humidity of the heated blow-by gas is thereby lowered below the relative humidity of the cooler blow-by gas still within the engine .crankcase. The heated gas flows through conduit 14 and, upon exiting the conduit through the perforations in loop 16, bubbles up through the water within the scrubber bottle. By the time the blow by gas bubbles through the entire water column, the gas is saturated with water vapor, i.e., its relative humidity is increased to 100%. The saturated blow-by gas leaves the scrubber bottle via conduit 19, and is returned to the engine combustion chambers through intake manifold 21.

Referring now to FIGURE 2, it can be seen that check valve 27 is normally held in the closed position by the action of gravity on the valve stem. However, if the pressure within bottle 11 becomes greater than the atmospheric pressure within the engine compartment (due to leaky intake valves or a blown head gasket), the stem of valve 27 is forced upwards, thereby opening the valve and venting the excess pressure to the atmosphere. This automatic venting action of valve 27 is a safety feature incorporated into the apparatus to prevent water in bottle 11 from being forced back through conduit 14 into the crankcase.

It will be apparent from the foregoing description that the apparatus of the invention is a closed-loop re-cyclin-g device which simultaneously ventilates the crankcase and humidifies the fuel-air intake mixture, thereby significantly reducing the concentration of unburned hydrocarbons in the engine exhaust gases. It should be noted, however, that several other advantages attach to the novel ventilation-humidification mode of operation of the apparatus. First, the corrosive acid vapor in the blow-by gas (chiefly sulfuric acid resulting from the combustion of sulfur in the gasoline) is removed from the re-cycle stream by the scrubbing action of the water in bottle 11. The removal of the acid vapors eliminates a major cause of engine wear, i.e., the condensation of acid vapor in the crankcase oil, thereby lowering the pH of the oil to a point where the oil has a corrosive action on metal engine parts. A further feature of the apparatus is that the water filled scrub ber bottle functions as an effective fine-mesh filter which removes particulate matter from the recycle stream. Crankcase vapors normally carry a considerable quantity of fine particulate matter in suspension. These fine particles, e.g., ash, iron oxide, lead sulfate, sulfur, ordinarily settle out on the surface of the crankcase oil, thereby leading to rapid clogging of the oil filter and eventual faulty lubrication of the engine. However, the simultaneous ventilation and scrubbing action of the present apparatus traps the suspended particles in the water in the scrubber bottle, thereby effectively removing them from the re-cycle stream.

Another feature of the apparatus is that the fine oil mist (the so-called oil ends) in the crankcase interior is insoluble in the water within the scrubber bottle. Consequently, this mist of oil passes through the scrubber bot tle, and is returned to the intake manifold, thereby resulting in continuous beneficial lubrication of the valves, cylinder heads, and tops of cylinders.

A further feature of the apparatus is that the gasoline which is lost into the crankcase on the compression stroke is insoluble in the water within the scrubber bottle. Hence, this gasoline, which would ordinarily be vented out the crankcase breather tube, is returned to the intake manifold and burned by the engine. Fuel economy is thus improved.

An important aspect of the operation of the apparatus is that the humidification function is entirely self-regulating. On days when the atmospheric humidity is high (resulting in a high partial pressure of water vapor within the crankcase), an equilibrium is reached between the humidity of the crankcase vapor and the humidity of the efiiuent gas from the scrubber bottle. Consequently, very little water is evaporated into the re-cycle stream from the scrubber bottle. Conversely, on day when the atmospheric humidity is relatively low (resulting in a low partial pressure of water vapor within the crankcase), water is evaporated from the scrubber bottle into the efiiuent gas at a relatively rapid rate. It has been found that one to two ounces of water are evaporated per galion of gasoline burned when the apparatus is operated on dry days, i.e., atmospheric relative humidity of 30 to 50%. It will be apparent from the foregoing that once the scrubber bottle is filled with water, the operation of the apparatus is entirely automatic. The rate of water evaporation automatically adjusts to changing conditions of atmospheric humidity.

The apparatus as shown in FIGURES l and 2 has no moving parts (except for check valve 27), and is virtually maintenance-free. It is only necessary for the user to occasionally replenish the water in the scrubber bottle, and to empty and refill the scrubber bottle with water when the layer of removed particulate matter reaches a thickness of one to two inches on the water surface.

As stated previously, one of the objects of the present method and apparatus is the reduction in concentration of unburned hydrocarbons by simultaneously ventilating the engine crankcase and humidifying the fuel-air mixture. The following table illustrates the reduction in hydrocarbon concentration obtainable with the present method and apparatus. The data in the table were obtained using a 1957 Chrysler automobile engine having an indicated mileage of 108,350 miles. The engine was driven through a 7-mode test cycle on a Clayton dynamometer. The exhaust gas was collected in an evacuated tank and analyzed for unburned hydrocarbons with a Beckman non-dispersive infrared spectrophotometer. Carbon dioxide, oxygen, and carbon monoxide were determined with a Fisher gas analyzer.

It can be seen from the foregoing table that installation of the present apparatus on the test engine reduced the concentration of unburned hydrocarbons in the exhaust gas by 41%. In addition, the concentration of carbon monoxide in the exhaust gas Was reduced by 67%.

What is claimed is:

1. Apparatus for reducing the concentration of unburned hydrocarbons in automobile exhaust gases comprising a container sealed at its upper end by a removable cap, an intake conduit communicated adjacent one end with the lower inten'or end region of said container and adapted at the other end for communicable connection to the crankcase interior of an internal combustion engine, an exit conduit communicated at one end with the upper interior end region of said container and adapted at the other end for communicable connection to the intake manifold of said engine, and a normally closed check valve mounted in said cap in communication with the interior of said container.

2. The combination of an intern-a1 combustion engine including intake and exhaust manifolds and a crankcase sealed from the atmosphere, at scrubber bottle partially filled with water and having a removable cap, an intake conduit extending into said bottle and communicating with the interior thereof at a location beneath the level of said water, said intake conduit communicably connected to the interior of said crank case and being looped closely about said exhaust manifold whereby the heat thereof is imparted to said conduit, and an exit conduit extending into said bottle and communicating with the interior thereof at a location above the level of said water, said exit conduit communicably connected to said intake manifold.

3. The combination of claim 2, further defined by a normally closed check valve mounted in said cap in communication with the interior of said bottle and arranged to open when the pressure in the bottle interior exceeds atmospheric pressure.

References Cited by the Examiner UNITED STATES PATENTS 2,166,720 7/1939 Gorleski 123-119 X 2,184,141 12/1939 Dodge 123-119 X 2,185,320 1/1940 Spearman 123119 2,646,784 7/1953 McKeeVer 123--1 19 X KARL J. ALBRECHT, Primary Examiner.

Claims (1)

1. APPARATUS FOR REDUCING THE CONCENTRATION OF UNBURNED HYDROCARBONS IN AUTOMOBILE EXHAUST GASES COMPRISING A CONTAINER SEALED AT ITS UPPER END BY A REMOVABLE CAP, AN INTAKE CONDUIT COMMUNICATED ADJACENT ONE END WITH THE LOWER INTERIOR END REGION OF SAID CONTAINER AND ADAPTED AT THE OTHER END FOR COMMUNUNICABLE CONNECTION TO THE CRANKCASE INTERIOR OF AN INTERNAL COMBUSTION ENGINE, AN EXIT CONDUIT COMMUNICATED AT ONE END WITH THE UPPER INTERIOR END REGION OF SAID CONTAINER AND ADAPTED AT THE OTHER END FOR COMMUNICABLE CONNECTION TO THE INTAKE MANIFOLD OF SAID ENGINE, AND A NORMALLY CLOSED CHECK VALVE MOUNTED IN SAID CAP IN COMMUNICATION WITH THE INTERIOR OF SAID CONTAINER.

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