US1825187A - Automatic fuel mixture regulator - Google Patents

Description

Sept. 29, 1931. H.HBNER l AUTOMATIC FUEL MIXTURE REGULATOR Filed Aug. 15. 1927 Patented sept. 29, 19314 PATIENT OFFICE HUGO HIIBNER, F MOSBACH, GERMANY AUTOMATIC FUEL MIXTURE REGULATOR Application led'August 15, 1927. Serial No. 213,126,

The function of the automatic fuel mix-l ture regulator is so to influence the compost tion of the fuel mixture in explosion motors, more particularly motor car engines, that for each load of the engine the most favourable mixing ratio of fuel and air is provided. The apparatus enables more particularly the deviations from the most favourable composition of the fuel mixture to be equalized,

which deviations are caused by the physical properties of fuel and air (differences in temperature, differences in specific gravity, density and the like). This correction is of great advantage for the reason that both the out-put of the engine and the fuel consumption are thereby favourably" affected. The variations in the fuel mixture caused by the different loads of the engine are completely automatically equalized, while those produced by physical influences and which occur very rarely are equalized by manual regulation.

The modern Carburettor has without doubt been brought to a high state of peri fection. It has become possible so to arrange it that it produces, for each position of the throttle, a mixture, in which the proportion of fuel to air is practically constant, and that it is also suitable for gasifying heavy fuels. On the other hand, is not possible to correct with it the variationsin the composition of the gas mixture caused by the heating of the engine and by external influence (the height of the barometer, moist air, temperature, and the like). This explains the fact that a Carburettor which, on starting the engine, delivers a fuel mixture which is perfect as regardsits composition, supplies, after the engine has become hot,

lo a mixture far too rich in fuel, "so that, on the one hand, the consumption of fuel is far too great and, on the other hand, the power of the engine drops. This change in the composition of the fuel mixture, on the engine becoming heated, is due to the fact that, on the one hand, the air expands owing to the heating and consequently has less oxygen per unit valume than cold air, and on the other hard the fuel becomes more liquid through 'he'heating and consequently more and in Germany August 21, 1926.

fuel passes out' of the nozzle in unit time than when in the cold state. Through the new' automatic fuel mixture regulator, a correct composition of the fuel mixture is produced in an unexceptional manner, as with it as much air is added automatically to the fuel mixture supplied by the carburettor as is required for forming the correct mixture. Hence, its use ensures a great saving in fuel and the highest possible development of power by the engine.

Various types of fuel economizers have been proposed, which are intended to improve the already-made gas mixture by the supply of additional air or to bring it nearer to a correct composition. Some of them are arranged for being regulated by hand and would in this form fulfil their purpose, if a fresh regulation was effected each time the engine changes its power, which, however, is usually not done for convenience sake, while others are arranged for automatic working. The latter kind of construction of the existing types of economizers does not sufficiently allow for the pressure conditions pertaining in the suction, pipe of the engine, and, in

-addition to this, their manner of working and' theiry ability to be regulated are so imperfect that it is rarely worth while introducing these automatic apparatus.

The new automatic fuel mixture -regulator completely avoids these drawbacks and inadequacies of the existing constructions intended for the same purpose, as it is easily adjustable, it may be adapted to any engine, and, when once set, works abso-f lutely automatically. It commences to function immediately the throttle is opened and becomes automatically inoperative on the said vthrottle being closed. It adds automatically to the gas mixture the quantity of additional air corresponding to each position of the throttle and to each speed of revolution of the engine. The apparatus is suitably mounted in the vicinity of the drivers seat on the instrument board, can be put into and out of operation by a simple manipulation from the drivers seat, and can be so adjusted that, on driving downhill, it supplies a large quantity of air to the motor for cooling it, with the throttle closed, prevents the consumption of fuel and the sparking plugs from becoming oily, and liberates a certain amount of braking action. The apparatus can also be'mounted directly on the suction pipe of the engine or by introducing into the same behind the Carburettor. In this case rodwork or Bowden control for regulating by hand must be provided.

The fuel mixture regulator according to the present invention makes use of the pressure conditions produced in the suction pipe by the suction action of the engine with respect to the outside air, which conditions vary with each fresh setting of the throttle and each time the speed of revolution of the engine varies, for displacing automatically a piston loaded by an opposing spring, such that a slide valve connected to the piston opens according to the requirements of the engine ports through which the fresh air can flow into the suction pipe and become mixed with the fuelmixture. A constructional example of the arrangements required for this purpose is shown in the accompanying drawings, in which Fig. 1 is a longitudinal section through the regulator which is connected by pipes to the Carburettor, and

Fig. 2 a longitudinal section of a regulator mounted in the suction pipe of an en ne.

igure 3 shows an elevation of the lower end of the pipe through which the additional air is admitted to the engine suction pipe, together with an elevation of a tubular rotary valve which is inserted in the pipefor controlling the supply of additional air by hand.

The regulator consists of a cylinder a, one end of which is closed and the -other open. Through the middle of the cylinder end a pipe b extends, which' is concentric with the cylinder and is fixed to the said cylinder end. In the cylinder a, and tting closely in the same, there slides the piston c which surrounds the pipe/b so as to be capable of sliding on it, but so as to iit closely to it. To the piston c is fixed the sleeve d. At its upper and lower end the said sleeve fits closely round the pipe?) while the middle part is recessed for preventing too great a' friction. At the sliding part where the sleeve d is fixed to the piston c, an internal annular groove Z is provided, having several holes m through which it communicates with theouter air. Through a spring k which may be wound cylindrically or conically according to requirements the piston c is lforced towards the open end of the cylinder a. In piace of a cylindrical or conical spring, two or more `springs of different strength maybe provided, inaccordance with the requisite spring pressure at diferent positions of the piston. In that part of the pipe b which is covered bv the sleeve d when the apparatus is inoperative, are a number of uniformly distributed holes o of equal or different size, which are distributed over about one-third of its periphery along the length of the recessed part of the sleeve el. Instead of one, two or more sets of rows of holes can be provided in the pipe. The pipe b is open at both ends. At one end. the tube e is inserted which" is open at its inner end and terminates at its outer end in a knob by means of which it can be turned about its longitudinal axis. This tube e is provided with a lateral slot p so that, by turning it, the holes o in the pipe b can be opened or closed row by row. Instead of one slot p two or more slots may be provided according to the number of rows of holes provided in the pipe b. The other end of the pipe b is connected by the pipe i (a rigid or flexible pipe) to the suction pipe of an engine, more particularly to the space 'l' between the throttle g and the suction valve. The cylinder a is connected by the branch g and the pipe h to that part of the Carburettor s which liesbetween the atomizer t (constriction of the Carburettor at the nozzle opening) and the throttle g. Over the open end of the cylinder a a sieve cap f is mounted which also surrounds the pipe b. The apparatus can be fixed by means of the flange n to the instrument board or any other suitable place. If the tube b be widened, as shown in Fig. 2, the apparatus may also be mounted behind the carburettor directly in the suction pipe of the engine. The pipe i is not required in this case and the pipe h becomes very short. For operating the tube c a lever u extends to the outside.

As stated above, the principle of the automatic fuel mixture regulator is based on the utilization of the differences in pressure according to the various parts of the pipe of the engine. The suction pipe may be divided into three zones, each of which has a different pressure. The first zone extends from the lower end of the carburettor to the middle of the atomizer. In this zone the external air pressure usually prevails. There will only be a certain amount of partial vacuum when the engine is working under full load. The second zone extends from the middle of the atomizer to the throttle. l`Vl7hen the engine is working with the throttle almost closed, there will be no vacuum in this part, as only a small amount of air is withdrawn by suction and sufficient air can flow in through the Carburettor opening. When, however, the throttle is opened further, a vacuum will be formed which becomes greater and greater the further the throttle opened, as the cross sectional area ofthe -suction pipe is reduced by the atom? izer of the Carburettor and under ordinary air pressureas much air cannot i'low through the 'atomizer as is; aspired by the engine. Thethird zone extends from the throttle to the suction valves. Here, owing to Athe suction action of the lengine when the throttle is closed, a considerable vacuum prevails which becomes less and less as the throttle is opened and when the throttle is quite opened becomes equal to the vacuum in the second zone.

The automatic fuel mixture regulator is connected to the engine by two separate pipes. One connection is established between the branch of the pipe b, extending out of the apparatus, and the third zone of the suction pipe, by the pipe z'. The cylinder a is connected by the pipe k with the second zone. The regulation of the air supply to the fuel mixture is effected as follows: when the engine is running and on opening the throttle, a partial vacuum is formed in .the second zone of the suction pipe, the said partial -vacuum will be imparted through the pipe 71, of the branch 0 to the cylinder a where it will act on the Apiston c. The piston c will be drawn by suction into the opening of the cylinder, until the pressure .of the spring k balances the suction. The sleeve d will move with the piston and will expose one ormore transverse rows of holes of the pipe b, according to the extent to which the throttle is opened,

or the amount of partial vacuum. -Air will flow through the opened ones into the interior of the pipe b and will be drawn strong- 1y by suction through the pipe z by the engine to the suction pipe of thefsame, owing to the considerable vacuum prevailing there, where it will mix with the fuel mixture. The further the throttle is opened, the greater will be the partial vacuum and the greater will be the number of rows of holes exposed until, when the throttle is entirely opened,

`all the holes will be exposed. 0n the throttle being closed again, the partial vacuum within the cylinder a will disappearl again,

andthe spring la will force the piston c with the sleeve d immediately back into the viliperative position, thus causing the air supo p y to cease. The partial vacuum in the Carburettor (between the atomizer and the throttle) besides being infiuenced by the amount to which the throttle is opened, is also influenced by the speed of revolution of the engine. The automatic apparatus makes allowance for this circumstance as well. When the engine is running at a high speed, more fuel is drawn in by suction, the vacuum becomes greater and the automatic apparatus provides a correspondingly greater quantity of air. Thus it regulates the supply ofadditional air in an ideal manner.

By means of the slide in the tube e by turning the latter as many longitudinal rows of holes may be exposed for the admission of air as the degreeof saturation ofthe fuel mixture supplied by the atomizer allows. This degree of saturation depends on the size of the fuel nozzle, whether the engine is cold or hot, whether the outer air is cold or warm and so on. All these contingencies can be" equalized by simply turning the tube e. If the tube e be partially or entirely withdrawn from the pipe b, the entire air opening is exposed and the entire quantity of air, which the cross sectional area of the pipe b will allow to pass through, will low to the engine. W'hen the throttle is closed, for instance, when driving downhill, the engine will consequently aspire only fresh air. This will iirstly cool the engine, secondly prevent the sparking plugs .becoming oily as the vacuum in the cylinder is reduced, thirdly, save fuel for the same reason and fourthly produce a braking action on the car. When the engine is not running, by opening the pipe b, any unauthorized person is prevented from starting the engine as no explosible gas mixture can be formed owing to the whole amount of additional air flowing in;

The provision of the smaller groove Z and the holes m is' intended to prevent the partial vacuum between the sleeve d and the pipe b being communicated to ythe space within the cylinder a and the function of the piston c being interfered with. This is effected by any particles of air -drawn by suction between the sleeve and the pipe being taken out from the space in the cylinder a but through the holes m from the outside air.

It is not necessary for the air te be supplied centrally with the tubular slide surrounding the air pipe and the piston.

These two parts can be separated or a Vfiat slide may be provided on one side only.

lVhat I claim is:

1. An apparatus for regulating the supply of additional air tothe suction pipe of an explosion motor, comprising the combination with the suction pipe and a throttle therein, of an air pipe having a plurality of rows of holes therein at one end and connected to thesuction pipe on the engine side of the throttle, a cylinder in open communication at one end with the suction pipe lon the atmospheric side of the throttle and surrounding said air pipe, said cylinder being closed at the end thereof 1n open communication with the suction pipe and openi at the opposite end and an assembly comprising a regulating piston and a sleeve connected to said piston, so as to be movable in unison therewith mounted' on the air pipe so asl to be slidable thereon with the regulating piston movable in the cylinder by the variation in pressure in the suction pipe on` the atmospheric side of the throttlev and the sleeve adapted to cover and uncover with its end remote from the regulating piston, the said holes in the air pipe for regulating the supply of air to the air pipe, said sleeve being recessed intermediately of its ends and having at the junction of the pistorf and sleeve an internal annular groove and holes in its wall communicating with the outside and said groove, a rotary sleeve in the air inlet pipe, said sleeve having air regulating openings ada ted to co-operate with the openings in t e air inlet pipe and. means connected to said sleeve for turning the sleeve by hand for varying the number of holes uncovered by the sleeve from the outside, as and for the purposes set forth.

2. An apparatus for regulating the supply of additional air to the suction pipe of an explosion motor, comprising the combination with the suction pipe and a throttle therein, of an air pipe having air inlet openings therein and interposed in the suct1on pipe on the engine side of the throttle so as to form an intermediate part of the suction pipe, a cylinder in open communication 'at one end with the suction pipe on the atmospheric side of the throttle and surrounding said air pipe, said cylinder being closed at the end thereof in open communication with the suction pipe and open at the opposite end, an assembly comprising a regulating piston and a sleeve connected v to said piston, so as to be movable in unison therewith, mounted on the air pipe so as to be slidable thereon with the regulating piston movable in the cylinder by the variation in pressure in the suction pipe on the atmospheric side of the throttle and the sleeve adapted to cover and uncover with its end remote from the regulating piston the said air inlet openings in the air pipe for regulating the supply of air to the air pipe in accordance with the suction produced on the atmospheric side of the throttle, the sleeve being recessed intermediately of its ends, and a rotary sleeve open at both ends, in the air inlet pipe, said sleeve having air regulating openings adapted to co-operate with the openings in the air inlet pipe.

3. An apparatus for regulating the supply of additional air to the suction pipe of an explosion motor, comprising the combination with the suction pipe and a throttle therein, of an air pipe havin air inlet openings therein and interpose in the suction pipe on the engine side of the throttle so as to form an intermediate park of the suction pipe, a cylinder in open communication at one end with the suction pipe on the atmospheric side of the throttle and surrounding said air pipe, said cylinder being closed at the end thereof in open communication with the suction pipe and open at the opposite end, an assemblycomprising a regulating piston and a sleeve4 connected to said piston, sok as to be movable in unison therewith, mounted on the air pipe so as to be slidable thereon with the regulating piston movableA in the cylinder by the variation in pressure inthe suction pipe on the atmospheric side of the throttle and the sleeve adapted to cover and uncover with its end remote from the regulating iston the said holes in the air pipe for regu ating the supply of air to the air pipe, said sleeve being recessed intermediately of its ends and having at the junction of the piston and sleeve an internal annular groove and holes in its wall communicating with the outside and said groove, a rotary sleeve in the air inlet pipe', said sleeve having air regulating openings adapted to co-operate with the openings inthe air inlet pipe and means connected to said sleeve for turning the sleeve by hand for varying the number of holes uncovered by the sleeve from the outside, as and for the purposes set forth.

In testimony whereof I have signed my name to this specification.

HUGO HUBNER.

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