US 3794302 A
A floatless carburetor for internal combustion engines comprising a suction tube, an air funnel therein, a spray tube opening within the air funnel, a throttle valve in the suction tube ahead of the spray tube, and a main nozzle disposed in a fuel chamber for delivering fuel to said spray tube. The main nozzle is formed as a mechanically and electrically controllable regulating valve. The valve member is drivingly connected to a magnetic ram which itself is connected by means of a resilient intermediary member to the linkage which operates the throttle valve. The magnetic ram can be actuated by electric currents the intensity of which is characteristic for the parameters which determine the preparation of the combustible mixture, whereby an electromagnetic adjustment can be superposed to the mechanical basic adjustment of the throttle valve.
Claims available in
Description (OCR text may contain errors)
United States Patent 1,
FLOATLESS CARBlJRETOR FOR INTERNAL COMBUSTION ENGINES Rudolf Diener, Zurich, Switzerland Autoelektronik AG, Chur, Switzerland Filed: Dec. 5, 1972 Appl. No.: 312,263
References Cited UNITED STATES PATENTS 2,856,910 10/1958 Goodridgem, 123 139 AW 3,566,847 3/1971 Scholl et al. 261/51 3,673,989 7/1972 Aono et al.;....- 123/32 EA [III/Ill/I/I/I V] I [451 Feb. 26, 1974 Primary ExaminerTim R. Miles Attorney, Agent, or FirmAnthony A. OBrien  ABSTRACT A floatless carburetor for internal combustion engines comprising a suction tube, an air funnel therein, a spray tube opening within the air funnel, a throttle valve in the suction tube ahead of the spray tube, and a main nozzle disposed in a fuel chamber for delivering fuel to said spray tube. The main nozzle is formed as a mechanically and electrically controllable regulating valve. The valve member is drivingly connected to a magnetic ram which itself is connected by means of a resilient intermediary member to the linkage which operates the throttle valve. The magnetic ram can be actuated by electric currents the intensity of which is characteristic for the parameters which determine the preparation of the combustible mixture, whereby an electromagnetic adjustment can be superposed to the mechanical basic adjustment of the throttle valve.
7 Claims, 1 Drawing Figure PATENTEDFEB 26 mm 7 w 5 ma 1 1 OOPOO 11 LL wk? FLOATLESS CARBURETOR FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The optimum composition of the air-fuel mixture for internal combustion engines depends on various parameters, such as the number of revolutions per minute, torque, barometric pressure, temperature and in certain cases also on the hygrometric condition of the air. It results herefrom that the preparation of the fuel mixture for internal combustion engines is a difficult task which hitherto could not be solved satisfactorily. The result of this short-coming is an insufficient combustion which causes an increase of the contents of toxic components of the exhaust gas. In .view of the environment protection, this fact can no longer be tolerated. Moreover, an unsatisfactory preparation of the fuel mixture can result in an increase of the required ignition energy which can cause trouble of the ignition system or failure of the ignition.
DESCRIPTION or PRIOR ART In the spray carburetors which up to now are almost universally used there is arranged in an air funnel formed as a venturi-nozzle a spray tube to which fuel or a fuel-air'mixture is fed. The air which is drawn through the air funnel produces a vacuum in the funnel,
which draws fuel from the spray t'ube, so that an air-fuel Such a type of spray'carburetoris not able to supply an. optimum air-fuel mixture for all operating or load conditions, since, for example, with higher motor speeds the quantity of .fuel discharged through the chokes. It is also known to constructtwo-stage carburetors, the so-called register carburetors, so that in the range of partial load, only onecarburetor stage is operating and the second carburetor stage is connected in full load range. Moreover, it is also known to vary the firing or ignition point or tomodify the cross section of the main nozzle by a conicalneedle adapted to adjust the nozzle output for partial loads.
Another manner of preparation of the combustible mixture is the direct or indirect injection of fuel; Pumps are used therefor, which have an adjustable stroke or which comprise valves the opening periods of which are exactly controlled. Injection pumps, however, are expensive, susceptible to cause trouble and require continuous attendance. Also here, it is difficult to obtain a precise adjustment.
SUMMARY OF THE INVENTION Therefore, thereis a real need in the art for carburetors of the aforementioned type which areof more simple design than prior art carburetors and which only comprise a main nozzle and a spray tube as principal components and notwithstanding are able to prepare an optimum composition of the fuel-air mixture for all operating conditions of the motor. Accordingly it is a primary object of the invention to provide a floatless carburetor which effectively and capably fulfills this existing need.
Another more specific object of the invention is the provision of an improved floatless carburetor which comprises a suction funnel, a spray tube within the suction funnel, a throttle valve and a main nozzle which serves for metering or dosing the delivery of fuel to the spray tube. The main nozzle is constituted by a mechanically and electrically controllable regulating valve which is connected by an elastic intermediary member with the linkage for adjusting the throttle valve, the electric control component of this regulating valve can be actuated by electric currents the intensity of which is characteristic for the prevailing parameters which determine the preparation of the combustible mixture.
In a preferred embodiment of the invention the regulating valve will be constituted by a magnetically adjustable ball valve.
By means of this arrangement it is possible to obtain that the sectional area of flow of the main nozzle and the position of the throttle valve, in a first approximation, are brought to a predetermined functional interrelation and that the sectional area of flow of the nozzle can be modified by electrical currents which are derived from parameters such as temperature, atmospheric pressure,R.P.M. of the motor, etc. The influenceof the different parameters on the optimum composition of the mixture theoretically does not need. to be known. However, it can be measured, so that function transmitting means can be constructed which deliver the required electric currents for modifying the sectional area of flow of the nozzle. The mechanical basic adjustment of the regulating valve accordingly is superposed by an electromagnetic adjustment.
By means of the carburetors according to the invention it was possible to reduce the toxic components in the exhaust gases of motors equipped with conventional carburetors to one fourth. This is far better than required by the new standard specification. It has been even possible to omit the speed-responsive and loadresponsive adjustmentof the firing angle, since due to the optimum preparation of the fuel'mixture, no ignition lag or delay occurs.
Advantages for the ignition system of the internal combustion engine are also obtained. It has been found that an optimum mixture can be ignited by shorter ignition sparks than a non optimum mixture and therefor the available ignition energy can be delivered suddenly to the combustible mixture. The result is a hot ignition spark which assists in maintaining the spark plugs clean for alonger period and in increasing their working life.
6. This results in that no pure fuel is delivered to the spray'tube, but already an air-fuel emulsion which improves the preparation of the combustible mixture. This procedure per se has already been used for preparing the idling or no load mixture in carburetors supplied with exhaust gas.
In order to provide a simple construction for the electromagnetically and mechanically adjustable regulating valve, it is preferred that the regulating valve is associated with a magnetic ram which is resiliently mounted between two diaphragms. It is possible to provide several excitor coils so that the regulating valve can be controlled independently by several function transmitters. It is also preferred to maintain a constant fuel pressure in the valve seat chamber of the regulating valve.
BRIEF DESCRIPTION OF THE DRAWING The preferred embodiment of the invention is described with reference to the accompanying drawing in which the single FIGURE represents a cross section through the carburetor according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT The illustrated example of a carburetor according to the invention comprises a suction tube 1 having an air funnel 3. In front of the air funnel 3 there, is arranged a throttle member 2 within the suction tube 1. The air funnel 3 is formed as a Venturi-tube into which extends a spray tube 4 ending in the zone of the highest vacuum. The spray tube 4 is supplied with fuel by means of a conduit 6 which leads from the spray tube 4 to the valve seat 7 of a regulating ballvalve. A tube connection 5 is branched off the suction tube 1. at a point abovethe throttle member 3 and leads to the conduit 6 The valve seat 7 can be closed by a ball 8 which is secured to a valve stem 9. This stem 9 is rigidly connected with a magnetic ram 13 by means of a screw and a sealing member 11.
I The supply of fuel to the valve seat chamber 23 is effected by a fuel pump 27 which draws the fuel through a conduit 28 and delivers it by a conduit 26 to the valve seat chamber 23. The fuel pressure in the conduit 26 amounts approximatively to 0.2- atmospheric excess pressure. The valve seat chamber is provided with a relief pressure valve corisisting of a valve flap 24 and a spring and which is so adjusted that the pressure in the valve seat chamberis approximatively 0.15 atmospheric excess pressure. Superfluous fuel is returned by a conduit 29 to the inlet of the fuel pump 27.
The magnetic circuit for actuating the magnetic ram 13 consists'of a core member 19,.a cylinder yoke 21, and a retraction ring member 22. The magnet winding which can comprise a single or multiple coil is designated by 20. The entire magnetic portion of the regulating valve is tightly closed on the top by a diaphragm through which the magnetic ram extends upwardly.
For securing the ram 13 to the diaphragm 14 there is The magnetic ram 13 is mechanically coupled by means of an elastic intermediary member with the linkage 30 for adjusting the throttling member 2. The elastic intermediary member consists of a spring 16 which bears at one end against the nut 15 and with the other end against a cap member 17. 18 designates the last hinge point of the linkage ahead of the cap member 17.
By means of the elastic intermediary member it is possible to superpose a magnetical shift to the mechanically produced adjustment of the magnetic ram.
The operation of the described carburetor according to the invention is as follows: The fuel is delivered to the valve seat chamber 23 by the pump 27 at aslight overpressure of about 0,2 atmospheric excess pressure and flows from there through the ball valve 7,8, the sectional area of flow thereof depending on the position of the magnetic ram 13. The fuel then flows through the tube 6 and is mixed with air supplied by the tube connection 5 and drawn out of the spray tube 4 by the vacuum prevailing in the air funnel 3.
The lever transmission between the throttle member 2 and the magnetic ram 13 can be so chosen that the sectional area of flow of the ball valve 7,8 corresponds to the-actual position of the throttle member during normal operation. When the motor is too cold so that a richer mixture is required, then the exciter coil 20 is supplied with electric current and the magnetic ram is lifted upwardly against the action of the spring 16, so that the sectional area of flow of the ball valve 7 ,8. is increased. The same action can beproduced for obtaining a movement of acceleration. In similar manner idling of the motor or running at no load'will be obtained by supplying current to the exciter coil 20. It is also possible to feeda constant current to the exciter coil and to correspondingly adjust the lever ratio between the throttling valve adjustment and the ram 13. When the mixture then becomes too rich, the current can be reduced.
The above description only gives a few examples of how a magnetic adjustment can be superposed to a mechanical adjustment. Also the influence of atmospheric pressure and atmospheric humidity can be compensated in similar manner.
It is accordingly possible with the carburetor according to the invention to produce an optimum air-fuel mixture for all parameters which occur in practical motor driving. This results in a reduction of the fuel consumption, a cleaner combustion and a smaller proportion of toxic exhaust gases, as well as in a reduced susceptibility to trouble of the ignition system, sincethe ignition of the mixture occurs more readily.
Further, the carburetor according to the invention is of a considerably simpler design than conventional carburetors and injection pumps, and its construction does not require the narrow tolerances called for in conventional carburetor construction and accordingly its fabrication' is more economical.
1. A floatless carburetor for internal combustion engines comprising a suction tube, a suction funnel formed within said tube, a spray pipe arranged to deliver fuel into the suction funnel, a throttle valve within said suction .tube, a main nozzle for metering the delivery of fuel to said spray tube, said main nozzle being formed by a mechanically'and electrically controllable regulating valve, aconduit for delivering fuel from said regulating valve to said spray tube, linkage means for mechanically adjusting said throttle valve, means for electrically controlling said regulating valve by a current responsive member, a valve seat chamber containing said regulating valve and adapted to contain fuel, and an elastic intermediary member connected to said linkage means and to said current responsive member for additional adjustment of said regulating valve in response to the intensity of the electric current, said intensity being characteristic of the parameters determining the preparation of the combustible mixture.
2. A carburetor according to claim 1, in which said throttle valve is arranged in the suction tube ahead of said spray tube, I 1
3. A carburetor according to claim 2, in which a tube is branched off said suction-tube and communicates 6 with said fuel delivery conduit leading to said spray tube.
4. A carburetor according to claim 3, wherein said regulating valve is formed by an electromagnetically stant fuel pressure prevails in said' valve seat chamber. i