US 2172957 A
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Sept. 12, 1939. D. FIRTH DUAL MANIFOLD EQUALIZER Filed Jan. 21, 1938 2 Sheets-Sheet l Sept. 12, 1939. F|RTH 2,172,957
DUAL MANIFOLD EQUAL-I ZER Filed Jan. 21, 1938 2 Sheets-Sheet 2 Patented Sept. 12, 1939 l UNITED STATES PATENT OFFICE DUAL MANIFOLD EQUALIZER David Firth, Flint, Mich., assignor to Borg-Warnler Corporation, Chicago, 111., a corporation of I linois Application January 21, 1938, Serial No. 186,170
4 Claims. (01. 123-52) This invention relates to internal combustion hence under these circumstances it is desirable engines and particularly to a novel arrangement to effect communication between the dual manifor supplying fuel thereto. folds for the purpose of equalizing the pressure The provision broadly of an equalizing passage therein. between the inlets of a dual manifold together It is the object ofmy invention to provide an 5 with a valve for controlling this passage under arrangement of means for carrying into effect the certain conditions has been disclosed heretoabove enumerated discoveries. These and other fore as, for example, in the patent to Timian No. objects of my invention will more fully appear 1,763,726 and in the patent to PatonNo. 1,87 2,800 from the following description taken in connection however, I have discovered animproved arrangewith the accompanying drawings, wherein: 10 ment of this valve together with means for mm Fig. 1 is an elevation partially in section of a trolling the same under most critically important p e red e od ent. conditions 7 not heretofore disclosed or ap- Fig. 2 is a vertical section taken on the line 2-2 preciated. V of Fig. 1.
Ihave discovered that in a dual feeding system 3 is a p a V ew W th the carbureter re 15 the respective manifold portions should be in moved nd h win r n p r in ection. communication under certain very specific con- Referring in detail to the drawings, I have ditions and individualized or separated from h w f r p rp f illustration, an internal communication with each other under certain Combustion engine indicated in dotted lines, other very specific conditions. I have further and having eight cylind r arranged be found that the degree of depression in the maniplied With uel in tW groups of foul y de s 20 fold itself is the most accurate index throughout each; cylinders n tw fiv n s comprising a the entire range of operation as to when these first p, d y d s three, four, eve nd dual manifolds should be in communication or i h mpr n a second p. A du l m niindividualized. Still further, I have found that fold indicated generally at is formed h a 25 the valve controlling this communication should first Conduit therein Communicating at s be operated from open to closed position quickly right end P w flange ect I for and in response to a predetermined degree of deconnection with cylinders l and 2 and at its left pression within the manifold irrespective of d portion w an connector 13 for connecwhether this depression is caused by a quick opention With Cylinders Seven and eight and provided 30 ing of the throttles to only partially full Open intermediate its ends with a vertical conduit porposition; by the faltering of the engine during tion l t for cooperation with one of the dual pasidling; or by the fuel opening of the th ttl sages of a carbureter (later to be described).
A duplex or two passage carbureter feed'will A' second conduit portion 15, the righthand end a produce very little more maximum power than a Of w c terminates in a 001111601301 flange o 0 single feed, but between engine speeds of from COIlIleOiJiOIl With Cylinders three d foul, the about 800 R, P. M. to about 2800 R, P, M,, th lefthand end of which terminates in connector duplex feed shows a definitely increased torque flange fo connection With cylinders five and over the single passage carbureter f d This six provided with a vertical conduit portion i8 gives aquicker acceleration especially on acceleralikewise for cooperation W t a Second dual D 40 tions from about 10 to about 60 miles per hour, sage of a carbureter. It is important to note that a better hill climbing performance and a marked vertical conduit portion l4 and vertical conduit improvement generally in what is referred to in portion F3 are each defined in p y a ommon the art as a better driving feel. These im- Vertical W proved results flowing from individualized or Mounted above vertical conduit portions 14 and dual feeds are not due to the increased size of the is a carbureter 29 0f the yp having ual air carbureting passage but are a result of the repassages 2| and 22 Cooperating With Conduit p duction of surge in the manifold. tions l4 and [8 respectively and provided with On the other hand it is found that under light throttles 23 and 24 respectively, mounted on a load conditions as when the motor is idling common shaft 25 under the control of the usual 50 normally or the car moving along under li ht manual connections including crank 26. load and the throttles only partly open, the This carburetor is provided with the usual fuel very high vacuum created within the respective supply including fuel bowl 21, fuel nozzles 28, etc., manifold portions is higher than that conducive a detailed showing of which is omitted for purto the most eificient operating conditions and poses of simplification. 55
The arrangement thus far described is well known and no claim is here mad thereto other than in combination with the novel equalizer hereinafter described.
Equalizer Common dividing wall l9 has a circular port 29 formed therein and supplied with a butterfly valve 30, mounted on shaft 3|, the opposite ends of which are journaled in the wall IS. The right end of shaft 39 (see Fig. 3) extends through the outer wall of manifold ill and supports one end of crank 32, the other end of which is connected by a link 33 with a bell crank 3.4 pivotally mounted on a bearing 35 attached to manifold l0. A second link 36 connects the other end of the bell crank 34 with the stem 3! of a piston 38, operating within a cylinder 39. This cylinder is attached to the first named portion I l of the manifold and has its interior in communication therewith through passage lfi for subjecting piston 38 to the varying pressures within the manifold. The left end of cylinder 39 is provided with threaded sleeve ll serving as a sealed bearing for stem 3?. Cylinder 39 is further provided with carefully calibrated compression spring 42 the left end of which is in contact with piston 38 and the right end of which is in contact with washer 43 carried on the inner end of screw 44 threadably mounted in threaded closure plug 45, serving as a means for accurately adjusting the degree of compression of spring ill. Screw M is maintained in its position of adjustment by lock nut 46.
Operation With the throttles 23 and 23 in their near closed idle position and the motor idling normally, a vacuum exists in the manifold portion H effective to draw piston 38 to the right and maintain valve 3:? in a partial or full open position to thus effect an equalization of the pressure between manifold portions H and I5. If the throttles are now quickly opened either to partial or full open position, the vacuum within manifold portion ii is suddenly dropped and spring 42 becomes eflective to move piston 38 to the left, effecting a closure of valve 30 to thus shut ofi communication through wall portion l9 and individualize the fuel supplies to the respective groups of cylinders. It is very important to note that this has the immediate result of rendering the full vacuum created by each group of cylinders effective upon its individual fuel supply. This condition maintains until the vacuum is built up to a degree where it is again effective to move piston 38 to the right and thus reopen valve 30 for again equalizing the pressures within the respective manifold portions.
The degree of manifold vacuum is the most accurate index of the conditions existing therein demanding a transition from a condition of equalization to a condition of individualization and vice versa, and therefore since spring 42 and screw 4 are capable of fine adjustment, this transition can be perfectly controlled. In accordance with my invention, valve 393 is thus rendered entirely dependent in its operation upon the vacuum condition within the manifold and is completely independent of any mechanical correlation with the throttle position, such as is inherently the case with the structures disclosed in the aforementioned patents.
Good results will be obtained if spring 4| is made to operate at a pressure in the manifold of about six inches of mercury or below to individualize the fuel feeding passages.
While I have disclosed my invention in connection with a specific embodiment thereof, it is to be understood that this is by way of illustration only; that many other applications may be made within the teaching of my invention; and that it is my desire to be limited only as indicated by the appended claims which should be given a scope as broad as the prior art will permit.
1. In a multi-cylinder internal combustion engine, the combination of an intake manifold having two spaced inlet passages serving different groups of cylinders, individual carbureting means supplying each of said passages including a throttle valve in each means, control means for said valves, and a third valve providing communication between said carbureting means, means urging said third valve toward closed position, control means for acting in opposition to said last named means, said third Valve urging means being operable in response to a relatively low vacuum such as occurs upon sudden partial or full opening of said throttle valves to effect a quick closure of said third named valve to thereby bring about individualized feeding of said groups of cylinders, said control means being operable responsive only to the development of a relatively high vacuum Within said manifold such as occurs either with the motor operating under light load with the throttles in a definite partly open position or with the throttles in idling position, to effect the opening of said third named valve to bring about communication between said fuel supply passages whereby to equalize the pressures therein under conditions of relatively high vacuum.
2. In a multi-cylinder internal combustion engine the combination of an intake manifold having two spaced inlet passages serving separate groups of cylinders, individual fuel supply conduit means for each of said inlet passages including a throttle valve in each conduit, an additional valve for controlling communication between said inlet passages, resilient means for urging said additional valve to closed position to thus shut off communication between said inlet passages and thus individualize the fuel supplies to said respective groups of cylinders when the degree of vacuum in the manifold is relatively low, means operable in response to the occurrence of a predetermined degree of relatively high vacuum, such as occurs with said throttles in nearly closed positions and the motor idling, or with the throttles in an intermediate position with the motor running under light load, to eifect the opening of said additional valve against the resistance of said resilient means to thus bring about communication between said inlet passages to thereby eifect equalization of the pressures in said passages, said means being further operable upon a subsequentdecrease of vacuum to permit said resilient means to again effect the closure of said additional valve to again individualize said feeds.
3. The arrangement as defined in claim 1 wherein said control means for said third valve comprises a cylinder, a piston in said cylinder, a
spring in said cylinder having predetermined resilient characteristics and effective to move said piston in one direction in said cylinder, said cylinder being in communication with said manifold whereby said piston is subjected to the vacuum conditions therein for moving the same against said spring, and operating connections between said piston and said equalizer valve for operating the same in accordance with the vacuum conditions existing in said manifold.
4. The arrangement as defined in claim 1 wherein said control means for said third valve comprises a cylinder, a piston in said cylinder, a spring in said cylinder having predetermined resilient characteristics and effective to move said piston in one direction in said cylinder, said cylinder being in communication with said manifold whereby said piston is subjected to the vacuum conditions therein for moving the same against said spring, operating connections between said piston and said equalizer valve for operating the same in accordance with the vacuum conditions existing in said manifold, and adjusting means for adjusting the degree of compression of said spring for rendering said control means responsive to various vacuum conditions existing in said manifold.