US2793846A - Carburetor with improved carburation - Google Patents

Description

y 1957 A. HEINRICH CARBURETOR WITH IMPROVED CARBURATION Filed Nov. l2, 1954 Mu&

United States Parent CARBURETOR WITH IMPROVED CARBURATION Adolf Heinrich, Munich, Germany Application November 12, 1954, Serial No. %8,500 Claims priority, application Germany November 14', 1 953' 3 Claims. (Cl. 261-65) There have already been known certain types of carburetor in which attempts were made to improve the manner in which carburation is carried out by providing for the ratio between the cross-sectional mixing area of the air duct and the diameter of the fuel dscharge aperture to be varied in dependence on the speed of the engine and the load conditions.

In one known construction designed to attain this' objective, use has been made of the well-known irs diaphragn' for the purpose of determining the crosssectional mixing area of the air duct and of varying said cross-sectional area. However, this attempted solution did not provide for the necessary dependability in oper ationnor was it unaifected by trouble; for this reason, no carburetor of this type has ever been adopted in practice.

Another avenue that has been explored in an efifort to tender the hereinbefore mentioned ratio between cross sections variable, which avenue has also been tried, is to arrange for the venturi-like mixing nozzle surrounding the fixed fuel discharge nozzle to be slidable in the direction of the axis of the suction pipe. tried by means of this arrangement to produce a sufficiently combustible mixture in the idling range of the engine by providing for the narrowest portion of the mixing nozzle to be sufficiently displaced in relation to velocities near the fuel discharge nozzle, whereafter the mixing nozzle was returned to its other extreme position where it remained as long as load conditions other than idling .had to be met. r w e It has also been suggested to displace the slidable mixing nozzle not only between its two extreme positions in a single operation, but continuously and gradually to displace the mixing nozzle in relation to the fuel discharge nozzle, the said displacement in this case being a function of the position of the carburetor throttle valve.

All of these known suggestions according to which the mixing nozzle is displaced in relation to the fuel spray nozzle or according to which an iris diaphragm is used to vary the smallest cross section of the air duet have this in common: the change in the ratio between the cross section of the air mixing nozzle and that of the fuel spray nozzle is effected in one sense only, that is to say, with an increase in engine speed and/or an increase in the cylinder charge and/or an increase in the load imposed on the engine, the change in the size of the iris diaphragm opening or the movement of the mixing nozzle relative to the fuel discharge opening is always eifected in one sense only. In all these cases the cross-sectional area of the air duet at the position of the fuel nozzle is enlarged as the output of the engine increases.

Now, in contrast to what has hitherto been known, the venturi-like mixing nozzle, which is arranged in a per se known manner to be displaced in the direction of the axis of the suction pipe, is arranged, according to the present invention, in such a manner that the position of the said nozzle is controlled in relation to the fixed fuel Patented May 28, 1957 spray nozzle of a carburetor in such a way that within i the control range of the carburetor from idling conditions to full load conditions the mixing nozzle is reciprocated, whereby the narrowest portion of the mixing nozzle which is initally positioned at the approximate level of the fuel spray nozzle is first moved away from the aperture of the spray nozzle and is subsequently. moved towards said aperture.

In this manner it is made possible to controlthe composition of the mixture in such way that a car'buretor in which this arrangement is used is capable of improvi'ng; the efficiency of power generation and of yielding favorable fuel consumption figures and operational transitions which have hitherto been impossible with known carbure tor control methods. A

The object of the invention is capable of meetin'g all known important requirements as regards the maintenance of a constant mxture composition and the preparation of a sufiiciently combustible mixture for 'certain' ranges of control. v

The object of the invention takes care of the requirement of mixing small air ows with sufficient fuel in the idlng range so as to produce a combustible mixture, and it also eliminates the well-known phenomenonof undesirable i enrichment of the mixture at high engine v Speeds which is caused by the disparity between the resistance offered to the inflowing air. and the flow resistance of the outflowing fuel, this disparity, in turn, being due; to the fact that the first-named resistance increase at a greater rate than the last-named resistance. The fact that the discharge opening ot the spray nozzle is approximately positioned in the region of the narrowest cross section of the mixing nozzle when the' engine is' Operating in the idling range, obviously meets the first of the two above-mentioned requirements in that. high air flow velocities are set up at the spray nozzle aper- First it was ture despite the small quantity of air drawn in per unit' time; the positioningof the spray nozzle opening outside the narrowest cross section with theengine Operating under part-load conditionspermits fuel to be saved. where it is possible without detractng from theeficiency with which power is developed; finally, the fact that within the full-load. range the spray nozzle opening is again' positioned within a smaller ;distance 'from the narrowest: cross section of the mixing nozzle takes `'care' of 'the re' quirement that within this load range fuel has to be introduced at a higher rate, while at the same time the undesirable enrichment of the mixture is counteracted by the vacuum acting on the spray nozzle aperture being reduced in relation to what it would be with the nozzle positioned at the narrowest portion of the mixing nozzle, this being due to the fact that in this control position the spray nozzle aperture is still slightly removed from the narrowest cross section of the mixing nozzle.

The details of the practical embodiment of the controls Operating the said mixing nozzle are of no relevance as regards the .principles underlying the present invention. The position of the miXing nozzle may be controlled in dependence on the position of the butterfiy valve at any given moment and thus also in dependence on the factors thus controlled, which factors determine the power output of the engine, or the position of the mixing nozzle may be controlled, among other things, by the pressure existing in the air inlet of the engine, by the quantity of mixture admitted or by the speed of the engine, the control then being efiected automatically, or by the provision of an adjusting linkage between the buttery valve and the displaceable mixing nozzle, the said linkage establishing a positive interdependence between the movement of the two control organs.

It is impossible to state a generally applicable law governing this interdependence, that is, the dependence of the length of travel of the mixing nozzle on the power data of the engine; it will be necessary to use empirical methods to establish the optirnum pattern of the control actions for different types of engines and for dierent sets of Operating conditions, this making it necessary for a carburetor the Construction of which is based' on the present invention to provide for easy adjustment of the controlled movements of the mixing nozzle as a function of those factors which afiect the power output of the engine. Represented in the appended drawing is an illustrative embodiment of a carburetor according to the invention, there being provided between the butterfly valve of .the carburetor and the displaceable mixing nozzle a linkage which is adapted to move these two control members in positively controlling interdependence, the said linkage being constructed in such a manner as to provide for easy adjustment of its individual links as regards their lengths and/or the position of their pivots so as to make it possible to vary the ratio between the controlling movements of the butterfly valve andi the mixing nozzle for the purpose of adapting the control system to different types of engines and their various sets of Operating conditions.

Figures 1, 2 and 3 of the appended drawing' illustrate one and the same carburetor according to the, invention,

the said figures respectively showing the two extreme positions, i. e. those for idling and full-load conditions, and one intermediate position of the displaceable mixing nozzle. In the drawing, reference numerals indicate the various parts as follows: 1, the air intake opening; 2, the fuel discharge opening or fuel spray nozzle; 3, the venturi-like mixing nozzle which is adapted to be displaced in the direction of the aXis of the suction pipe;

4, the butterfly valve or throttle; 5, the pivot axis of' 1 end of the -connecting rod 7.

It will be appreciated that the embodiment illustrated as an example, having a control linkage 6, 7, 8, is adapted, by changing the effective length of the connecting rod 7 and by hookng its ends into suitabiy selected holes inthe levers 6 and 9, respectively, to be adjusted within a wide range to meet the requirements given by the type of engine under consideraton and its various Operating conditions.

The three different operative positions of the carburetor illustrated in the drawing indicate that with the butterfly valve fully opened the displaceable miXing nozzle has been almost completely returned to its original position which it assumes with the butterfly valve closed, and that with this particular position the aperture of the spray nozzle is still slightly removed from the narrowest portion o' construction of the mixing nozzle.

I claim:

1. A carburetor having a variably positioned pivotal butterfly valve, air intake means, fuel spray means between said butterfly valve and said air intake means, a mixing nozzle movably positioned adjacent said fuel spray means, and control means responsive to variations in position of said butterfly valve for moving said mixing nozzle away from and thereafter back toward 'said fuel spray means as the position of said butterfly valve is increasingly varied in a single preselected direction, said control means comprising a first pivotal arm coupled to said butterfly valve and movable .therewith, a second pivotal arm connected to said mixing nozzle, anda linking arm connected to both said first and second pivotal arms whereby unidirectional variations in position of said butterfly valve eiect bidirectional variations in the position of said mixing nozzle.

2. The carburetor of claim 1 including means `for Variably connecting said linking arm at differing positions on each of said first and second pivotal arms.

3. The combination of claim 1 wherein said mixing nozzle comprises venturi means having a region of restricted cross-section, said control means being operative to position said restricted region substantially adjacent said fuel spray means for both closed and fully opened positions of said butterfly valve.

References Cted in the file of this patent UNITED STATES PATENTS 1,1s1,2s6 Rowell Aug. 24, 1915 1,198,o43 Meara Sept. 12, 1915 1,s19,698 Bow et al. Aug. 18, 1931 1,942,00S Schramm Jan. 2, 1934 FOREIGN PATENTS 435339 Italy Mai-. 25, 1948

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