US2678035A - Control mechanism for carburetor type internal-combustion engines - Google Patents

Description

y 1, 1954 R. E. UHLENHAUT CONTROL MECHANISM FOR CARBURETOR TYPE INTERNAL-COMBUSTION ENGINES Flled March 23, 1950 Fig.2

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CONTROL MECHANISM FOR CARBURETOR TYPE ENTERNAL-COMBUSTION ENGINES Rudolf E. Uhlenhaut, Stuttgart-Gaisburg, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Application March 23, 1950, Serial No. 151,363

Claims priority, application Germany March 25, 1945 9 Claims. (01. 123-108) This invention relates to a control mechanism or entirely out out. In the simplest way this cutfor carburetor type internal combustion engines, ting out may be accomplished thereby that a for example, automobile engines. Objects of the lever, linked to the control linkage, is, with represent invention are primarily to provide an imspect to the carburetor control member, adjustprovernent in engine power, improved flexibility 5 ed beyond the dead-center position. Thus the of control as load changes are made, better startcarburetor throttle may be actuated by the linking torque, high efficiency as well in the lower age first to open and thereafter to close. By in as in the upper range of engine loads and, eventerposing suitable play the movement of the contually, security against over-running when extrol linkage may also affect the throttle of the ceeding a permissible top speed. m main carburetor.

In order to obtain in carburetor type internal The application of such a control prevents the combustion engines a smooth transition as load engine from reaching a speed above a permissible changes are made, or when opening or closing number of revolutions since it throttles down or the throttle, and to secure a good behavior of stops the engine assoon as the permissible speed the engine at part load, it is suitable to keep the is exceeded. clear passage area for the air on the carburetor In the accompanying drawing two forms of air funnel relatively narrow. However, such a carburetor control mechanisms, in which the proportioning has the disadvantage that, the invention is embodied, are illustrated by way of higher the engine speed the lower becomes the example, and volumetric eificiency. Already at intermediate Fig. 1 illustrates a carburetor control mechaspeeds the power decreases, resulting at higher nism with mechanical centrifugal governor, and speeds in an essentially lower efficiency. Fig. 2 a carburetor control mechanism with hy- In contradistinction thereto a feature of the draulic governor. invention-particularly in order to remove these In Fig. 1 rigidly secured to the engine it is disadvantagesessentially consists therein that shaft 2 on which the rotor 3 of a centrifugal the passage area for the carburetor air is govtype speed governor is rotatably mounted, which erned in dependence on the speed by means of on support arms a carries fly weights 5. lhe aspeed governor, particularly in a manner wherespeed governor with its optionally two-piece, by, with increasing engine speed or when exhousing-like part 5 is driven by the crank or ceeding a predetermined speed, the passage area camshaft or by any other suitable rotating part of the carburetor air is increased. Such a conof the engine by means of a v-belt l. The control is suitably obtained by providing an auxiliary trol arms 8 of the fly weights 5 act upon govcarburetor in addition, for example, to a low proernor pins 9 which are shiftably supported in the portioned main carburetor. This auxiliary carhousing-like part 6. Mounted on the shaft 2 buretor is out 01 essentially SO, only when th is a governor sleeve lil whose collar-like rightengine exceeds a given speed. The auxiliary carhand end i i embraces the flange E2 of the housburetor is preferably in parallel with the main ing 6 on the outside. Springs [3 surround the carburetor and provided with. a separate throtpins 9 and are supported on one side against the 1 v 1v Cutting in y take place gradually or flange l2 and on the other side against the colinsilantly at p p if desired. -Open lar-like left-hand end it of the governor sleeve throttle of the main carburetor. Preferably, the Ill, so as to cause the latter together with the auxiliary carburetor is also cut out at part load governor pins 9 to be forced towards the left (entifely p ly) at all engin p against the action of the fly weights 5. A c0n- V s i, at l a O ly in h owe p d a etrol sleeve 15 is either rigidly or non-positively A further feature of the invention consists connected with the pins 9 or sleeve til. At low therein that, when a definite upper limit speed speed (the fly weights 5 being still at rest) this is exceeded, the passage area of the carburetor sleeve 15 is in the left-hand end position illusis reduced, or still further reduced, particularly trated in Fig. 1, however, as the weights 5 are in such a manner that the auxiliary carburetor, moved by the centrifugal force it is gradually being in parallel with the main carburetor, is moved towards the right.

gradually or instantly, entirely or partly cut out The movement of the control sleeve i5 is trans-- when the upper limit speed is exceeded. Simulmitted by means of a bell-crank H5 and a rod ll taneously the speed governor may, as the upper to a lever is which in turn, by means of a rod 29 limit speed is exceeded, also affect the main carconnected to the joint 19, and which may be lonburetor in a manner whereby the same is partly gitudinally adjustable, transmits the movement to the lever 2! of the throttle 22 of the auxiliary carburetor. The lever 2| is connected with the lever 23 of the throttle 24 of the main carburetor by means of a strap 25 which embraces the pin 26 with lost motion in the form of a longitudinal slot 2?. The lever 23 for the throttle of the main carburetor is operated in the usual manner through a rod 28, for example, by depressing the accelerator pedal.

The double carburetor 29 is, for example, developed as down-draft carburetor. Each of the throttles 22, 2A is situated in a separate air passage, each of them being provided with a separate fuel jet and eventually separate float housmg.

In the drawing, the governor and control linkages are illustrated in their respective position with released accelerator pedal (that is no-load) and at low speed. As the accelerator pedal is depressed, for example, against the action of a conventional release spring, and the rod 23 accordingly moved in the direction of the arrow, the throttle 24 of the main carburetor opens, whereas the throttle 22 of the auxiliary carburetor remains closed, since the strap 25, according to the lost motion 2?, can move towards the right until the throttle 24 is wide open or nearly wide open without carrying along the pin 26 of the lever 2!. If desired, more or less shortly before the throttle 2A is wide open, a partial opening of the throttle 22 may also take place by causing the pin 26 to be carried along in the slot 21. The slot, in this case, may be proportioned substantially shorter than shown in the drawing.

As the engine speed increases and the fly Weights 5 swing outward, their movement is transmitted through the pins 9 and links l5, l6, I1, 18, i9, to the lever 21 of the throttle 22 of the auxiliary carburetor. In the course of this movement, the lever I8 can swing in a total angle of the magnitude on which is composed of an angle ,8 and an angle 7. After moving as far as 6, the joint is is situated at a point I9 which lies on the straight-line connecting the fixed fulcrum point as of the lever l8 and the joint 25 in the position 26' of the latter. In this position the throttle 22 is wide open, the engine has reached its maximum permissible speed. The throttle 24 of the main carburetor is in a position corresponding to the position of the accelerator pedal, and it is, therefore, also wide open.

If, however, the latter is not the case and, therefore, the throttle 24, for example, only partly open, then the governor force and the spring force of the accelerator pedal can be matched in such a manner that the governor cannot overcome the pressure of the release spring of the accelerator pedal and is therewith rendered ineifective for no-load or part load, or can only become effective to an extent corresponding to the lost motion for the pin 26 as released by the links 28, 25.

As the engine speed exceeds the limit determined by the position IQ of the lever I8 (the fly weights being swung further out), the joint I9 is moved beyond the dead-center position i9 into the position is" with the result that the joint 26 returns into the position 26" and the throttle 22 of the auxiliary carburetor is again partly (or, eventualy, also entirely) closed. Inasmuch as the throttle 24 of the main carburetor has likewise been open it may in this case, for example, with a correspondingly shorter slot 21, likewise be carried along in closing direction by the strap 25. A spring, permitting such movement, may

4 be interposed between accelerator pedal and rod 28.

In Fig. 2 the control of the throttle 22 of the auxiliary carburetor, or of both carburetors 22 and 24, depends upon the action of a hydraulic type speed governor. The latter consists of a two-part housing 32 fastened, for example, to the carburetor 29 by means of a bracket 3 i. The interior of the housing 32 is in communication with the water pump of the cooling water circulation system of the engine through a line 34 and provided with a diaphragm 35 actuated by the pressure of the cooling water. The pressure exerted by the diaphragm is transmitted through a link 36 to a bell-crank 3i and thence via a rod 38, which may be longitud nally adjustable to the lever 2! of the carburetor 22. At low engine speed, the diaphragm 35 is locatedeither due to its own elasticity or owing to the action of a separate spring counteracting the pressure of the cooling water--in the left-hand end position shown in the drawing, in which position the throttle 22 is closed.

With rising engine speed and consequently rising cooling water pressure, the diaphragm 35 is pushed beyond its intermediate position up to its right-hand end position. As an intermediate speed is reached by the engine (corresponding to an intermediate position of the diaphragm 35 and a movement covering angle [3 of the bellcrank 31) the joint 39 between the lever 31 and the rod 33 is moved in turn into a dead-center position 39 which corresponds to the wide-open throttle 22. At a further movement, covering angle 7, up to the end position 39" of the joint 39, the throttle 22 and, if desired, also the throttle 24 are operated in closing direction in order to prevent over-running of the engine. In other respects the same principles are applicable as in the embodiment according to Fig. 1.

If desired, the connection between the throttle of the auxiliary carburetor and the throttle of the main carburetor, by means of the strap 25 or the like, may be omitted. In this case, as the permissible speed is exceeded, a reduction in power or speed is solely obtained by cutting out the auxiliary carburetor. The air passage area of the main and auxiliary carburetors may, as in the illustrated embodiments, be equally large, or also variously proportioned. The air passage area of the main carburetor, for example, operated by the accelerator pedal, may as well be smaller or larger than that of the auxiliary carburetor. Main and auxiliary throttles may also, by way of example, be arranged on a joint fulcrum point, in which case the coupling between both throttles may be accomplished either on the throttle shaft itself, or also outside on the linkage. Instead of a mechanical or hydraulic type speed governor, a pneumatic type speed governor or the like may be provided for. The hydraulic speed governor may also be actuated, by Way of example, instead of by cooling water pressure by the pressure, of the lubricating oil, or by means of another liquid circulated by the engine.

In contrast to the mechanical control, the hydraulic control generally is such that the pressure of the liquid, and therefore fundamentally also the actuating stroke, increases relatively slowly in the lower speed range and relatively fast in the upper speed range. Such a control is, circumstances permitting, especially suitable, since thereby a quick cut out is rendered possible as the permissible speed is exceeded.

Furthermore, it may prove to be especially suitable to arrange the speed governor on the vertical shaft of the distributor or the ignition system of the engine and have it driven by this shaft.

As already stated, the rod 26 of Figure l or so of Figure 2 may be longitudinally adjustable, in which case it comprises two telescoping parts 20 and 253' or 38 and Eli, whereby the length of the rod may be varied Within desired limits.

It will be obvious to those skilled in the art that the details of construction may be varied from those shown and yet the essentials of the invention be retained. I therefore do not limit myself to such details.

What I claim is:

1. In an internal combustion engine, two carburetion devices essentially in parallel, comprising: a main and an auxiliary carburetor, a control member [or the air passage area of the main carburetor, a control member for the air passage area of the auxiliary carburetor, a speed governor depending for its action upon a change in engine speed, a transmission mechanism for actuating the control member of said auxiliary carburetor by means of said speed governor, and a lost motion coupling member between said control mechanism of said main carburetor and that of said auxiliary carburetor, said transmission mechanism and said lost motion coupling mechanism being adapted to enable said speed governor, at substantially wide-open air passage area of said main carburetor, to govern the control member of said auxiliary carburetor substantially over the entire range of speed control, and wherein at fully closed air passage area of said main carburetor the actuation of the control member of said auxiliary carburetor by said speed governor is inhibited.

2. In an internal combustion engine, a main carburetor, an auxiliary carburetor, a speed governor depending for its action upon a change in engine speed of said internal combustion engine, a control mechanism for said main carburetor operable by exterior forces, a control mechanism for said auxiliary carburetor, a transmission linkage between said speed governor and said control mechanism of said auxiliary carburetor, and a couplim linkage between both of said control mechanisms including a lost motion whereby, with the control mechanism of said main carburetor adjusted to full load, said speed governor is enabled to operate the control mechanism of said auxiliary carburetor over the entire range of speed control, and conversely, with the control mechanism of said main carburetor adjusted to no-load, said speed governor is prevented from affecting the control mechanism of said auxiliary carburetor.

3. In an internal combustion engine, the combination according to claim 2 in combination with an operating linkage for the control mechanism of said carburetor whereby said control mechanism of said main carburetor may be adjusted to decreased load by means of said operating linkage, at low speeds of the internal combuston engine substantially unhindered by said speed governor, and conversely, at higher engine speeds only against the action of said speed governor.

4. In an internal combustion engine, a main carburetor, an auxiliary carburetor, a control mechanism for said main carburetor, a control mechanism for said auxiliary carburetor, a speed governor depending for its action upon a change in engine speed, a transmission linkage affecting said control mechanism of said auxiliary carburetor by means of said speed governor, comprising: an intermediate lever and a linkage member connected thereto being arranged and connected in such a manner that, said speed governor comes into action with rising engine speed, said intermediate lever and said linkage member corniected thereto are caused to move toward and past their reciprocal dead-center position and thereby effect a movement of the control mechanism of said auxiliary carburetor at first increasing said air passage area during the movement toward said dead center position and thereafter decreasing said passage area during movement past said dead center, and a coupling linkage including a lost motion between the control mechanism for said auxiliary carburetor and the control mechanism for said rnain carburetor enabling said transmission linkage, with said main carburetor adjusted to full load, to make its movement past the dead-center position independent of said control, and conversely, with said main carburetor adjusted to decreased load, being prevented from carrying out said movement.

5. In an internal combustion engine, the combination according to claim 2 including, means for adjusting said transmission mechanism between said spced governor and said control mechanism of said auxiliary carburetor.

6. In an internal combustion engine, the combination which comprises two carburetion devi es in parallel, one control member each for controlling the passage area for the carburetor air of each device, the control member of at least one of said carburetion devices being operable from outside, a speed governor depending for its action upon a change in engine speed, and a transmission mechanism for actuating the control mechanism of at least other of said carburetlon devices in response to the action of said speed governor, and wherein said speed governor and said transmission mechanism are adapted to influence one of said carburetion devices in such a manner that said air passage area of said one carburetion device is decreased when a definite top speed is exceeded.

'7. In an internal combustion engine, the combination which comprises two carburetion devices in parallel, one control member each for conrolling the passage area for the carburetor air of each device, the control member of at least one of said carburetion devices being operable from outside, a speed governor depending for its action upon a change in engine speed, and a transmission mechanism for actuating the control mechanism of at least the other of said carburetion devices in response to the action of said speed governor, and wherein said speed governor and said transmission mechanism are adapted to infiuence said other carburetion device in such manner that with rising speed said air passage area is first increased and thereafter decreased when a definite top speed is exceeded.

8. In an internal combustion engine, the combination which comprises two carburetion devices in parallel, one control member each for controlling the passage area for the carburetor air of each device, the control member of at least one or" said carburetion devices being operable from outside, a speed governor depending for its action upon a change in engine speed, and a transmission mechanism for actuating the control mechanism of at least the other of said carburetion devices in response to the action of said speed governor, said transmission mechanism being so constructed and connected to said speed governor and carburetion devices that to some extent said speed governor also actuates the control member of said one device within a portion only of the actuation range of said other device.

9. In an internal combustion engine, the combination which comprises two carburetion devices in parallel, one control member each for controlling the passage area for the carburetor air of each device, the control member of at least one of said carburetion devices being operable from outside, a speed governor depending for its action upon a change in engine speed, and a transmission mechanism for actuating the control mechanism of at least the other of said carbure- 8 tion devices in response to the action of said speed governor, said transmission mechanism being so constructed that, when a definite speed is exceeded, said air passage area of the other of said carburetion devices is also reduced, at least at wide-open air passage area.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,432,444 Dake Oct. 17, 1932 2,209,401 Jennings, Jr July 30, 1940 2,249,439 Stryker July 15, 1941 2,317,625 Mallory Apr. 27, 1943 2,386,669 Ericson Oct. 9, 1945 2,443,084 Rhodes June 8, 1948 2,527,354 Christian Oct. 24, 1950

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