The present invention relates to a method and a device for supplying a combustion-promoting liquid medium into the suction line of an internal combustion engine. It is previously known that by supplying combustion-pro¬ moting liquid additives into the suction line of an in- ternal combustion engine, a more efficient combustion, a decreased fuel consumption, cleaner waste gases and a higher engine power may be achieved. Known devices for this purpose include a closed container for the liquid having diffusor means disposed in the lower part of the container, said diffusor means being connected with the ambient air by means of a conduit for supplying air and discharging air bubbles into th^e liquid within the con¬ tainer. The container is connected with the suction line of the internal combustion engine by means of a conduit opening into the upper part of the container. Under the influence of the vacuum in the suction conduit ambient air is caused to pass in the form of air bubbles through, the liquid within the container for absorbing liquid and further transporting it as an air/liquid composition to the suction line of the internal combustion engine, where it is mixed with the fuel/air mixture from the carburettor or the like if engines of the carburettor- type are involved, and with the suction air when diesel engines are concerned. In order to influence the combustion in the most efficient way, the combustion-promoting medium should be supplied into the engine in a certain concentration and in a very finely divided state together with the oxygen required for the combustion. The, concentration of additives in the form of

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micro-droplets, suspended in the gas extracted from the container, depends on the one hand on the quantity of micro-bubbles produced per unit of time within the liquid in the container, and on the other hand on the air volume above the liquid level in the container. The result is that by using a diffusor unit which due the vacuum prevailing at the suction side of the engine dis¬ charges a certain quantity o-f bubbles per unit of time in the liquid, the concentration of micro-droplets in the extracted gas is highly dependent on the air volume above the liquid level in the container. This air volume is subject to variations partly depending on changes in the liquid level in the container, partly to a high de¬ gree depending on the container size. In order to meet the demand for additive for different engine sizes and different engine types by using a certain diffusor unit for generating the bubbles, the containers are manufac¬ tured in varying size series, e.g. in volumeseries of e.g. 1 litre, 2 litres, 5 litres etc. This involves un- desirable variations with respect to the concentration of the additive in the form of micro-droplets suspended in the extracted gas. Theoretically, this problem can be solved by providing a complete unit for each -cylinder and thus achieving a largely unchanged concentration of additive in the extracted gas. In actual practice, this solution is unacceptable and results in extensive piping and space problems in connection with installa¬ tion in the engine house, and also in maintenance prob¬ lems. In actual practice the container size is adapted to existing size intervals for the engines, resulting in said variations with respect to the concentration of additive in the extracted gases.

The object of the present invention is to provide a simple method and means for supplying the suction line of an internal combustion engine with a combustion-

_^ promoting liquid medium, the concentration of micro- -droplets of the additive in the gas being sucked into the suction line of the engine being maintained essen¬ tially constant or within acceptable limits, regardless of the size of the container for the additive and using one and the same unit for the production of micro-bubb¬ les.

According to the invention the objects referred to above are achieved by the measures and characteristics referred to in the characteristic clauses of the appen¬ ded claims.

In the following the invention is described by reference to two embodiments illustrated on the appended drawings, in which FIG 1 shows a section through a first-embodiment of an arrangement for carrying out the method in accordance with the invention, and FIG 2 shows a section through a container having a bubble chamber. which may be detachably inserted into the container, said bubble chamber including a bubble production unit and an extraction arrange¬ ment.

In the method in accordance with the invention the vacuum on the suction side of an internal combustion engine is utilized in a manner known per se for supply¬ ing a combustion-promoting liquid medium into the suc¬ tion line. Due to the vacuum ambient air is thus sucked into a container, which contains said liquid medium, and is distributed within the liquid by means of a diffusor, the air bubbles formed absorbing liquid drop¬ lets which, suspended in air, are sucked into the suc¬ tion line of the internal combustion engine and mixed with the fuel air or with the fuel/air mixture, and is supplied into the combustion chamber for promoting the combustion. As mentioned above, it is desirable that the

combustion-promoting liquid is supplied into the suction line and into the combustion chamber in a condition as finely divided as possible in order to contribute to the greatest possible extent to efficient combustion. It is also desirable that the atomized liquid be supplied in a high concentration so that the total reaction sur¬ face of the combustion-promoting medium supplied becomes as large as possible and so that the concentration of additive in the form of micro-droplets suspended in the gas sucked from the container into the engine, is kept essentially constant at a desired value, suitable for the engine involved, regardless of the volume of the container for said additive.

In the method according to the invention this is achieved by making the diffusor discharging the air bubb¬ les within a volume of liquid in the container, which is separated from the remaining container liquid, the air suspension of said medium being sucked into the internal combustion engine from the space aboversaid separate liquid volume in the container. As indicated by the embodiment shown in FIG 1 this is brought about by arranging a single separating wall in the container, said wall separating a liquid volume wherein said dif¬ fusor is arranged and into which said suction conduit opens. The quantity of micro-bubbles- are thus discharged within a liquid volume being subject to very moderate variations regardless of the size of the container as such. By this means, a concentration of micro-droplets is obtained in the air/liquid suspension sucked out from the container, which is subject to very small, ful¬ ly acceptable variations regardless of the total amount of additive in the container. According to an embodiment which has not been illustrated, it is possible to make the separating wall in the container adjustable so that the volume of the bubble chamber may be adjusted within

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certain limits. This provides a further opportunity for controlling the concentration of additive and supplying air so that an optimally advantageous, combustion-pro¬ moting effect is achieved. According to the embodiment shown in FIG 2 the separating wall is designed as a vertical cylinder, open at the bottom, and containing a bubble generating diffusor, the upper end of said cy¬ linder being fastened to the filling cover in which also the conduit for supplying ai -to the diffusor as well as the suction line for air/liquid sus-pension open. The cylindrical separating wall thus form a complete bubble generating unit which, by means of the container filling cover is detachably fastened in the container and may be attached to an optional container. FIG 1 illustrates, schematically an arrangement for carrying out the method according to the invention. The arrangement consists of a closed liquid container 1' for the combustion-promoting liquid 2. By means of a separat¬ ing wall. 12 a chamber 1A is formed within the container, the generation of micro-bubbles taking place within said chamber and the air/liquid suspension also being extracted to the engine from said chamber. At the top and the bottom the separating wall 12 is provided with ap ^~ e.rt-u es 13, 14 so that the portions 1A and 1B of the container 1,which are separated by wall 12 communicate for permitting free flow of liquid between the portions. A filling connection 3 for filling the container with liquid to a predetermined level is provided in the upper wall above container section 1B, i.e. that section of the container which by means of a wall 12 is separated from chamber 1A in which the generation of micro-bubb¬ les takes place. The filling pipe is closed by a cover 4.

Disposed close to the bottom of chamber 1A, which is defined by means of separating wall 12, is a diffusor

5 having a pipe connection 6 extending within the chamber 1A, through the upper wall thereof and being there in connection with the air surrounding the con¬ tainer. The diffusor 5 consists of a diffusor body of a porous material, the pores of which forming a great number of small εir channels densely distributed over the diffusor body, so that air being sucked in via con¬ duit 6 are distributed within the diffusor and are dis¬ charged within the liquid in the chamber 1A in the form of fine air jets.which on emerging into the liquid form a large quantity of micro-bubbles. A conduit 7 opens in the upper wall of the chamber 1A of the container, the opposite end of said conduit opening into the suction line 8 of an internal combustion engine, not shown. The conduit 7 which may be a fixed conduit or a hose-, has a uniform cross section or shape along its entire length without any restrictions or obstructions to the free flow of the air/liquid suspension through the conduit. The suction conduit 6 of the diffusor 5, which opens above the upper wall of the container chamber 1A is at its free end provided with a restriction in the form of a washer 9 having a hole 10 drilled therein. Further provided at the free end of conduit 6 is an air filter 11 having a low flow resistance. The container as well as the conduits and other equipment components are made from a material which is resistent to the liquid which is to be stored in the container, e.g. stainless steel. The container 1 is also provided with a level indicator, not shown in the figures, and with the necessary attach- ment means for attaching the container at a suitable location in the vicinity of the internal combustion en¬ gine.

Under the influence of the vacuum in the suction conduit 8 of the internal combustion engine, air is sucked in through the air filter 11, restrictor washer 10

and the conduit 6 to the diffusor 5. From the diffusor 5 the air which has been sucked in is discharged in the form of fine air jets into the liquid surrounding the diffusor 5 in the container chamber 1A, resulting in the emission within the separated liquid volume of a great number of micro-bubbles flowing upwards towards the surface of the liquid within said container portion and on emerging therefrom tearing away micro liquid droplets, said droplets beinα suspended in the air and through conduit 7 transported further and discharged into the suction- conduit 8, where they are mixed with the fuel air or with the fuel/air mixture. Due to the throttling action of the restrictor washer 10 a high velocity is imparted to the air, this having proved to favourably influencing the number of micro-bubbles which per unit of time are formed and dis¬ charged within the liquid volume confined within con¬ tainer portion 1A, which in turn favourably influences the concentration of micro-droplets in the air/liquid suspension formed. The restrictor washer 9 is preferab- ly made replaceable in order to render possible the insertion of restrictor washer with various degrees of restriction depending on the requirement in each indi¬ vidual case. Alternatively, the restrictor washer 9 may be replaced by a restricting nozzle which is step- -wise or continuously adjustable thereby facilitating adjustment of the flow restriction to a suitable value in a simple manner.

Thanks to the fact that the generation of micro- -bubbles in accordance with the invention takes place in a liquid volume in the container which is separated by means of the partition wall 12, a fairly constant concentration of micro-bubbles is obtained per unit of volume regardless of the container size, as well as a relatively constant concentration of additive in the air/liquid suspension which is sucked into the engine

from container section 1A. In a modification of the arrangement in accordance with the invention, which is not shown in the diagrams, it is possible to vary the volume of liquid available for the production of micro- -bubbles by making the partition wall 12 d spl-aceabte inside the container, and thus by thosemeasures facilitating control of the concentration of micro-droplets in the air/liquid suspension sucked out from the container. The diffusor 5 used in the described arrangement according to the invention is, as mentioned, designed to finely dividing the air into a number of densely distri¬ buted fine air jets. To achieve this, the diffusor should preferably be made from a porous material, e.g. sintered metallic particles or ceramic sintered material. Metal- lie or ceramic icrofilters of the type used in cleaning filters or e.g. flue gas cleaners may thus be used as th *.e* material in the diffusor 5_..

The embodiment according to the invention, which is shown in FIG 2, differs from the embodiment according to FIG 1 essentially in that the partition wall 12A has been designed as a cylindrical tube which by means of a threaded connection at the top is attached to the under¬ side of the container cover 4A, extending downwards to the bottom of the container 1. At its lower portion the tube 12A is provided with apertures 13A through which the chamber 1A, separated by the tubular partition 12A, is connected to the surrounding liquid volume 1B in the container 1. A diffusor unit 5 is dis¬ posed within the cylinder 12A, near its lower end, and the supply conduit 6A through which air is supplied from the atmosphere to the diffusor -5 is attached to the cover 4A projecting upwards from the top face of the cover 4A, where the projecting tube end 6A is provided with an air filter 11 and a restrictor washer 9 having a hole 10 drilled therein in a manner corresponding to that in the

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embodiment according to FIG 1. Furthermore, the cover 4A is provided with an upwardly projecting connection piece 16 which by means of a hose 7A or some other kind of duct connection is connected to the suction conduit 8 of the engine.

Under the influence of the vacuum on the suction side of the engine air is sucked, in a manner correspond¬ ing to that described in connection with the embodiment according to FIG 1, from the surroundings through the air filter 11 and the conduit 6A to the diffusor 5 through which air in the form of large quantities of micro-bubb¬ les is discharged into the Tiquid within the volume 1A partitioned off by the tube 12A. On emerging into the chamber 1A above the liquid level, micro-droplets are torn away from the liquid by the micro-bubbles, said micro-droplets being suspended within the air above the liquid level and being sucked through conduit 7A into the suction line 8 of the engine.

Thanks to the fact that the generation of micro- -bubbles according to the invention takes place in a separate liquid volume within the container partitioned off by the partition wall 12A, a relatively constant concentration of micro-bubbles per unit of volume is ob¬ tained, as previously described, regardless of container. size, and also a relatively constant concentration of additive in the air/liquid suspension sucked from cham¬ ber 1A into the engine. As the liquid level in the con¬ tainer drops a certain increase with respect to the concentration of micro-bubbles per unit of volume in the separate liquid volume is obtained, but since the air volume above the liquid level of the separate liquid volume at the same time increases, a balancing effect is obtained with respect to the concentration of micro-drops suspended in the air volume above the liquid level, which contributes towards keeping the concentration of additive

in the form of micro-droplets suspended in the gas being sucked into the engine suction line substantially constant.

In the embodiment described above and illustrated in FIG 2 the partition wall 12A having the form of a cy- lindrical tube fastened in the cover 4A, together with the diffusor unit disposed therein, air supply conduit 6A, filter arrangement 11 and connection piece 16, forms a unit which in a simple manner may be transferred from one container to another, and which also may be installed in containers of different size. This facilitates the use of containers for the additive, which are designed as non-returnable packages which may be offered for sale in various sizes and which may b suspended in the engine chamber by means of a simple holder. By inserting the unit described above into the - aperture of the container, said non-returnable package forms such an arrangement for supplying a combustion-promoting liquid medium into the suction line of an internal combustion engine as is intended according to the present invention. When the liquid in one container has been used up, the conduit 7A is released from the connection piece 16, the cover 4A together with the tubular partition wall 12A and the diffusor unit 5 is removed from the container by unscrew¬ ing the cover 4A. A new, filled container is then inser- ted in the holder, its transportation cover is removed whereupon the "bubble production unit" is inserted into the filled container by being screwed onto the aperture connection of the container by means of cover 4A, the conduit 7A being then connected to the connection piece 16.

The invention which has been described above by reference, to the embodiments illustrated in the diagrams is not restricted thereto but may be subject to variations within the scope of the appended claims. Thus, the cham- ber in which the micro-bubbles are produced may of course

include more than one diffusor unit. Also the "bubble production unit" described in connection with FIG 2 may naturally be installed permanently within a container of the type described in connection with FIG 1.

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