US2853985A - Pressure responsive throttle control means for internal combustion engines and the like - Google Patents

Description

Sept. 30, 1958 P. LANDRUM 2,853,985

- PRESSURE RESPONSIVE THROTTLE CONTROL MEANS FOR INTERNAL COMBUSTION ENGINES AND. THE LIKE Filed'Feb. 2. 1956 2 Sheets-Sheet 1 m mm INVENTOR. PORTER LA NDRUM ATTORNEYS Sept. 30, 1958' P. LANDRUM 2,853,985

- PRESSURE RESPONSIVE THROTTLE} CONTROL MEANS FOR INTERNAL COMBUSTION ENGINES AND THE LIKE Filed. Feb 2, 1956 2 Sheets-Sheet 2 INVEN TOR. 1 0A TE R LA NDR UM PRESSURE RESPONSIVE THROTTLE CONTROL MEANS FOR INTERNAL COMBUSTION EN- GINES AND THE LIKE i Porter Landrum, Birmingham, Ala. Application February 2, 1956, Serial No. 563,064

2 Claims. Cl. 123-103 My invention relates to pressure responsive throttle control apparatus for internal combustion engines and the like. v In present day automobiles the demand for high performance characteristics such as high rates of acceleration and high cruising speeds, together with the desire for fuel economy has resulted in various compromises in engine design'and operation. Thus, in some modern production automobile engines compression ratios are as high as. to 1. However, this high ratio can only be fully ,usedat relatively high or cruising speeds. At low speeds, in order to prevent damage to the, engine, it is necessary to do two things: a t jgiFlISti To .fire each cylinder considerably past the optimum firing point thereof; and, a g

Second: To over-enrich the fuel-air mixture to assure less than the ,optimum rate of burning of the mixture. z' obviojusly and as is well known, this results in'very poor fuel economy at low and intermediate speeds. Further,,,crlank case dilution is not infrequent, especially after the piston rings becomeworn. It thus is well under,- stood that with prior carburetion and controls therefor, it impossible to maintain optimum ratios between the fuel-air mixture and theignition timing at all engine 'speeds:', Therefore, when the accelerator pedal is suddenly depressed at low engine speed, the modern high compression ratio automobile engine is performing at its lowest thermal efiiciency, all because of the foregoing compromises in design and operation.

. In view of the foregoing the primary object of my invention is to overcome the above difficulties in such manner that the engine operates always at optimum efiiciency, regardless of engine speeds, and to eifect .this automatically, without the necessity of the operator of the automobile having to perform any additional control functions other than operating the automobile in the normal'manrier.

2,853,985 Patented Sept. 30, 1958 of the character designated which makes possible an increase in the compression ratio of internal combustion engines to a point considerably above the present day practices with present day carburetion and controls, without dangerin injury to the engine parts.

Another object of my invention is to provide a control system for the throttle valve of an internal combustion engine which comprises an expansible member connected to openand close the throttle valve, together with con: nections from said device both to the throttle valve and T to a manually actuated control together with a third connection from said device to the manifold of the auto: mobile engine, all for the purpose of providing means interposed between the manual throttle control andsaid throttle which is effective to maintain the throttle set at the optimum operating condition of the engine, inde: pendently of the manual setting, but within a range limited to, a maximum opening as determined by said manual setting.v V a A further object of my invention is to provide a throttle control system for internal combustion engines which thefengine to move the throttle valve from a position of low engine speed to the positionofengine speed as determined by the setting of said manual means, andto do so in such manner that the engine operates at optimum efliciency ati allspeeds between said lower speed and said maximum speed; 1,

Another object ofmy invention is to pi'ovide throttle control means for the engine which is responsive to the manual control of the operator to the extent that the maximum throttle opening is determined by the operator depressing the accelerator pedal, and in which there is interposed between the manual control and the carburetor throttle valve a pressure mechanism which is effective to open the throttle valve up to said'maximum position .only as fast as the engine can use the'additional fuel.

My invention contemplates the provision of means as- I sociated with a manually control accelerator pedal or other manual throttlecontrol which is efiective to move the throttle valve in such manner that the engine operates at optimum fuel efficiency while accelerating, said means being responsive to the pressure existing in the intake manifold, whereby, the ignition timing of the engine may Another object of my invention is to provide apparatus A rhore'detail object of my invention is to provide a throttle valve control system embodying the .usual accelerator. pedaland linkage leading to the throttle valve inwhich there is interposed in said. linkage system a fluid pressure cylinder having relatively movable parts, one' of its movable-parts being operatively connected to the accelerator pedal and the other movable part being operatively connected to the throttle valve, the space in said cylinder between said relatively movable. partsbeing connected to the intake manifold of the engine.

A still further and more detail object is to provide a hydraulic throttle control system in which the accelerator pedal is operable to depress a fluid filled bellows, this bellows being connected by a line to a throttle control bellows through a vacuum control bellows, the latter bellows having a vacuum connection to the intake manifold of the engine, the parts being so arranged that upon selecting the speed of the engine by pressing downwardly on the accelerator bellows, the actual engine speed is governed by the sub-atmospheric pressure in the intake manifold, thereby to obtain the aforesaid result ofgoptimum operating efficiency ofthe engine at allspeed 's Briefly-,-my invention consists of means to controlthe throttle valve 'of the engine in which the accelerat or' pe'dal or other manual control isremployed as a means to select the maximum'speedfat which it is desired to operate the engine. Associated with, the control system is either a mechanical control device such as a fluid pressure cylinderTor a ,pneumaticcontrol device such as a hydraulic cylinder or expansible bellows eachof which is connected tohthe intake manifold of the engine, a The throttle eontrol valve-is 'operatively connected, mechanically intone case andhydraulicallyin the other, to the control device. Upon depressing the accelerator pedal the maximum opening-of the throttle valve is selected. Howevendue "to the fact that there is no straight through mechanical or hydraulic'connection to the throttle valve,"the throttle valve is .not immediately opened. The opening of the .valv'eiis under control .of the pressure existing in the intak'e'manifold and the control means associated directly with jt hje valve opens the valve in response to the subatmospheric pressure in the intake manifold. However, in opening the valve from the lower speed position to the maximum opening selected by the accelerator pedal, the control means automatically opens the valve precisely in accordance with the fuel requirements of the engine throughout the speed range represented'by said throttle settings. Fuel is supplied to the engine in such manner, throughout that entire range of speed, as to cause the engine to operate at optimum efliciency. Thus, and by reason of the fact that at all times there is automatic control over the throttle for each engine speed below the maximum selected by the manual control, the timing of the engine may be set so that the engine fires precisely at the optimum point in the cycle. Furthermore, due to this control over the opening of the throttle valve there is no occasion to over-enrich the fuel as has heretofore been necessary. The engine thus accelerates at optimum efficiency and produces maximum power for the fuel consumed at all engine speeds. The further advantage of being able to increase the compression ratio of the engine flows naturally from this control over the throttle valve. The engine can be made with as high compression ratio as is practical for the fuel to be consumed and for the strength of the parts. Such engine will operate at low speeds with maximum efliciency as well as at high speeds with like efficiency. My invention thus ties together for overall control of engine efiiciency the intake manifold pressure control of the spark setting and the present intake manifold pressure control of the air-fuel ratio which exists in present day automobile engines. Furthermore, my invention may be applied to existing engines without material change in any of the parts thereof.

Apparatus illustrating features of my invention is shown in the accompanying drawings forming a part of this application in which:

Fig. 1 is a somewhat diagrammatic view of my invention embodied in a hydraulic throttle control system;

Fig. 2 is an enlarged detail sectional view taken generally along line IIII of Fig. l;

Fig. 3 is an enlarged detail view taken generally along line IIII'II of Fig. 1;

Fig. 4 is an enlarged detail sectional view taken generally along line IVIV of Fig. 1;

Fig. 5 is a wholly diagrammatic view of a mechanical form of my invention, certain of the parts being broken away and in section and showing the device in the position assumed with the engine at rest;

Fig. 6 is an enlarged detail sectional view certain parts being broken away and in section and showing the parts in the position they assume when the engine is at rest;

Fig. 7 is a view similar to Fig. 6 and showing the position of the parts with the engine idling; and,

Fig. 8 is a detail sectional view taken generally along line VIIIVIII of Fig. 7.

Referringnow to Figs. 1 to 4 inclusive, I indicate diagrammatically at 10 the manifold of an internal combustion engine. Mounted on the intake manifold 10 is a carburetor indicated generally by the numeral 11 and which -has the usual butterfly or throttle control valve 12. The valve 12 is mounted on the usual pintle 13 and has on one end thereof an operating arm 14.

Mounted on the floor 16 of the automobile is the usual manually operatedaccelerator pedal 17. The pedal may be hinged at 18 in'the customary manner.

My improved hydraulic throttle valve control system will now be explained. As the description thereof proceeds it will become readily apparent that various kinds of fluid pressure devices may be used as actuators in my system, but for the sake of clarity I will describe them as being expansible bellows. This system comprises essentially three parts namely, an accelerator bellows indicated generally at 19, a throttle control bellows indicated generally at 21, and a manifold pressure responsive bellows indicated generally at 22.

The bellows 19 may consist essentially of an expansible cylindrical metal body portion 23 which has end plates 24 and 26. The end plate 24 may carry a ball 27 which slides under the lower surface of the pedal 17. 'It will be understood that the heads are fluid tight in the expansible metal portion 23.

The throttle control bellows 21 is essentially like the bellows 19 and consists of an expansible cylindrical body portion 28 and heads 29 and 31 made fluid tight thereto. The head 29 carries a bracket 32 which is connected to the outer end of the arm 14 by means of a pin 33. The lower head 31 carries a ball 34 which may rest rotatably in a seat 36 carried by a plate 37. The plate 37 is mounted in suitable manner on the manifold and carburetor assembly so that the bellows 21 may open and close the throttle valve 12 as will be explained.

The bellows 22 consists of an outer cylindrical body portion 35 of expansible material and an inner cylindrical body portion 46 of similar material having a fluid space a therein. The inner and outer bodies are made fluid tight to heads 38 and 39.

The head 39 is screwed into the manifold 10 by means of the threaded stem portion 41. Drilled through the head 39 is a passage 42 which is in communication with the space 43 inside the body portion 35 and surrounding the inner body 40. A passage 44 is connected to a lateral opening or passage 46 so that there is a connection from outside the head 39 into the space 4011.

The bellows 19 is connected by a line 47 to the passage 46 in the head 39 of bellows 22. Also connected to the passage 46 is a line 48 which terminates at a support bracket 49. The end of the line 48 near the bracket 49 is connected by a flexible hose 51 to an opening 52 in the lower part of the bellows 21.

From what has been described the operation of this modification of my invention may now be explained and understood. The hydraulic system consisting of the bellows 19, the line 47, the inside space 40a of the cylindrical body portion 40 of the pressure responsive bellows 22, line 48, flexible tube 51, and bellows 21, are filled completely with fluid. In order to assure that there is no air in the bellows provision in the form of vent plugs 53 are provided in the tops of each of the fluid spaces of the bellows. It will be understood that the bellows 19 and 21, due to the natural characteristics of the material from which they are made, tend to compress substantially to their full limit of movement. On the other hand, the heads 38 and 39 of bellows 22 are moved apart by the inherent characteristics of the outer and inner cylindrical body portions 35 and 40. Therefore, when the parts are completely filled with fluid and the engine is not running, the bellows 19 and 21 are substantially collapsed whereas the bellows 22 is substantially completely distended.

Under the conditions just mentioned it will be apparent that when the engine is started the pressure existing in the manifold 10 exists also in the space 43 by reason of the connection afforded by the passage 42. As soon as the engine starts the manifold pressure in space 43 tends to collapse both of the cylindrical body portions forming bellows 22, forcing fluid from the space 40a into the bellows 19, raising the accelerator pedal. It will be understood that the bellows are so constructed that more force is required to distend bellows 21 than is required to distend bellows 19, including lifting the weight of the accelerator pedal. Under the conditions just mentioned the engine now is idling with the throttle valve fully closed. Assuming that it is desired to increase the speed of the engine the accelerator pedal is depressed in the normal manner. This forces hydraulic fluid from the bellows 19 into the space 40a and also tends to force some of it into the bellows 21. The amount of fluid, however, of the total displaced from bellows 19 that enters bellows 21 is depedent upon the collapsed position of bellows 22. The collapsed position 5. of bellows 22 is in tiirndepedent upon the pressurein themanifold 10. Therefore, the effect of depressing the accelerator pedal 17 is to determine the maximum setting of the throttle. The actual moment of the throttle from closed position to the selected maximum position occurs when the pressure in the space 43 decreases sufliciently partially to collapse the cylindrical body portions '35 and 40 of the bellows 22, thereby forcing fluid from the space 40a into bellows 21, distending the latter, opening the throttle. The fact that the pressure at any instant in manifold 10 determines the amount of fuel that the engine can use at that instant assures that the throttle moves only in such manner that the engine is supplied with ex actly the right amount of fuel and no more, throughout its range of speed from the lower speed to the selected higher speed. Obviously, by suitable adjustments of the engine the setting of the manifold pressure controlled ignition timing can be arranged so that the engine fires at the optimum time.

Referring now areparticularly' toFigs. 5, 6, 7 and 8, I show a mechanical system embodying substantially the functionatfeatu'res of the-hydraulic system 'Whi'ch -already has been described. In this instance the accelerator pedal 17 is connected by linkage 56 to one end ofa throttle control cylinder indicated generally by the numeral 57.

Referring now particularly to Fig. 6 it will be seen that the throttle valve control cylinder 57 consists of a cylinder proper 58 having heads 59 and 61 therein. The head 59 is secured to the rod 56 and has vent opening 59a therethough. The head 61 is provided with a passageway 62 which is connected by means of a nipple 63 and a flexible hose 64 to the intake manifold of the engine.

Slidably mounted through a suitable fluid tight bushing 66 in the head 61 is a rod 67 which is pivotally connected at 68 to the arm 14 which controls the throttle valve 12. The inner end of the rod 67 carries a fluid tight piston assembly 69. Interposed between the inner end of the head 61 and the adjacent side of the piston 69 is a coil spring 71.

The operation of the modification of my invention just described may now be explained and understood. With the parts assembled as shown it will be seen that with the engine at rest, that is, with atmospheric pressure in the manifold and hence inside cylinder 58, the parts assume the position of Figs. and 6. The accelerator pedal in the position shown inFig. 6 of the drawings is in its full depressed position, because with the engine not running spring 71 has separated the head 61 and piston 69 until the piston is chock-a-block with the head 59 of the cylinder.

Let it now be assumed that the engine is started. As soon as the sub-atmospheric pressure in the manifold is established in cylinder 58 which occurs almost instantaneously, the cylinder 58 moves to the right as viewed in Fig. 6 and 7 under the influence of a light tension spring 77 and due to reduction of pressure in cylinder 58. Thus, starting in the position of the parts shown in Fig. 6 cylinder 58 is in its lefthandmost position with the throttle valve 12 closed, when the engine is not is for the reasonthafthe fiiel frieefl turn depehdent upon the pressure in the manifolds refore,"and 'afs heretofore been stated, throughoutallranges of speed from the lower speed corresponding to the lower throttle setting to the higher speed corresponding,to'the' rriaximum throttle opening selected by depressing the' accelerator pedal, theengine operates at maximum'fuel' efiiciency.

From the foregoingit will be seen that I have devised an improved throttle control system for internal combu s j tion engines. Insofar as I now am aware, the major practical application of my'invention' lies primarily in its use on modern day automobile engines; In'actiml operation I have found that my invention is entirely satis running. When the engine starts a reduction of pressure in the cylinder 58 permits spring 77 to move the cylinder to the right, raising the accelerator pedal and simultaneously compressing spring 71. With the parts in the position of Fig. 7, in which the engine is idling, and the accelerator pedal raised, let it be assumed that it is desired now to open the throttle. The accelerator pedal is depressed in the normal way to select the maximum opening desired for the throttle. Depressing the accelerator pedal moves the cylinder 58 to the left as viewed in Figs. 6 and 7 whereupon, due to the change in the pressure in the cylinder 58 rod or link 67 moves to the left, opening the throttle. However, the rate at which the link 67 moves to the left is depedent, auto matically, upon the need of the engine for fuel. This factory and that marked increases -in eflicienc'y and smoothness of operation resultfmm its use. i 1'55?! 5 By way of exampleyl haVe-emplOyed that form of my invention shownin Figs; 5 to 8, inclusive, on a 6 model, 8 cylinder,chevroletautomobilei; The engine 'of' 'that particular'automobile'has a standard 8 to l compre'ssidri ratio. Without 'making any change in the automobile other than applying my'inverition" thereto,-I note the fol lowing improvements in operation:-*

(1) In normal city traflic I increase the gasoline mile age from an average of 9.2 miles per gallon to an average of 13.4 miles per gallon. These tests were conducted under as nearly similar conditions as I could attain. At constant speed, highway driving, at 60 miles an hour, I note relatively little improvement in gasoline mileage, acceleration, or other performance.

I now removed the cylinder heads from this same automobile engine and machined them down to increase the compression ratio to 12 to 1. With my invention applied to such engine I note the following improvements in operation:

An increase in gasoline mileage for city driving from 9.2 miles per gallon for the standard compression ratio without my invention, to 13.4 miles per gallon with my invention and with the compression ratio increased to 12 to 1. For highway driving at 60 miles per hour, I decreased the fuel consumption from 15.9 miles per gallon for the standard compression ratio without my invention, to 19.8 miles per gallon for the same car with my invention applied thereto and with the compression ratio increased to 12 to 1. This automobile was equipped, during all these tests, with an automatic transmission.

In the tests just mentioned I made no change in the setting of the ignition timing and no change in the carburetor parts. The inside diameter of the cylinder 58 in the example given was 1% inches. Its active travel was 3 inches. However, it will be apparent that these dimensions may vary for each individual engine to which my invention is applied. The spring 71 was selected so that under no conditions with fully depressed accelerator pedal would the pressure in the manifold fall below minus 5 inches mercury, gauge. With my invention applied thereto, there was no appreciable decrease in the performance of the automobile with respect to acceleration, hill climbing, top speed, or otherwise. I note a marked increase in the general smoothness of the engine, particularly during periods of acceleration. I noted no predetonation of the fuel even though the compression ratio had been raised and even though the octane number of the fuel used during the test was the so-called regular grade, that is, without anti-knock additives, which latter is designated as premium quality. As an indication that the increased compression ratio of the engine is employed to a very large extent over present practice, the above identified Chevrolet automobile equipped with my invention cruised at 60 miles per hour with an intake manifold pressure of minus 17 inches mercury, gauge, as compared to minus 15 inches mercury, gauge, for the same automobile without my invention applied thereto and without increasing its compression ratio.

While I have shown my invention in but two forms, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

,1. In a control system for the throttle valve of an internal combustion engine having an intake manifold, a first variable volume fluid unit, manual means for changing the volume of said first unit, a second variable volume fluid unit, means operatively connecting the second unit to the throttle valve in such manner that an increase in volume of the second unit moves the throttle valve toward open position, a third variable volume fluid unit, a fluid line connecting said three units, and a pressure responsive unit associated with said third unit and operatively connected to the inside of the intake manifold, said three units and said line being substantially filled with an incompressible fluid with the first and third units at substantially maximum fluid capacity and with the second unit at substantially minimum fluid capacity.

2. In a control system for the throttle valve of an in- 8 ternal combustion engine having an intake manifold, a first normally distended compressible fluid tight bellows, a manual throttle control for compressing the bellows, a second normally compressed expansible fluid tight bellows, a third normally distended fluid tight bellows, a fluid line connecting all of said bellows to form a closed fluid pressure system, there being a supply of substantially incompressible fluid filling said system, means operatively connecting said second bellows to said throttle whereby upon expansion of said second bellows the throttle moves toward open position, and means to collapse said third bellows in accordance with the pressure in said manifold, whereby upon collapsing the first bellows said fluid flows into the second bellows and thereby opens the throttle valve in accordance with the pressure in said manifold.

References Cited in the file of this patent UNITED STATES PATENTS 20 2,246,348 Coffey June 17, 1941 2,627,850 Willum Feb. 10, 1953 2,672,855 Thomas Mar. 23, 1954

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