US2098718A - Supercharger mechanism for internal combustion engines - Google Patents

Description

Nov. 9, 1937. H. CAMINEZ ET AL 2,093,718

SUPERCHARGER MECHANISM FOR INTERNAL COMBUSTION ENGINES Original Filed March 17, 1933 Patented Nov. 9, 1937 UNITED STATES SUPERCHARGER MECHANISM FOR INTER- NAL COMBUSTION ENGINES Harold Caminez and Norman H. Gilman, Indianapolis, Ind., assignors to General Motors Corporation, Detroit, Mich., a-corporation of Delaware Original application March 17, 193s, Serial No.

661,327. Divided and 1936, Serial No. 80,734

6 Claims.

Our invention relates to multiple cylinder internal combustion engines designed, particularly, for dirlgible balloon, airplane and like aeronautical service; and particularly to engines of the V type, having two' cylinder blocks arranged at an angle to one another'and each block having a plurality of parallel cylinders. In the embodiment of our invention illustrated and hereinafter described twelve cylinders are present in two blocks arranged at an angle of 60 degrees to one another.

This present invention has to do with supercharging'mechanism for increasing the volume of air or combustible mixture supplied to the cylinders of the engine, and includes driving means for the usual centrifugal pump which forms a part of such mechanisms; and the drawing accompanying and forming a part of this specification illustrates'only such parts and features of the engine as are necessary to an understanding of this present invention.

In the drawing wherein the preferred form of our invention is illustrated:

Figure 1 is a view showing a section upon vertical central planes indicated by the broken line ll of the schematic plan view, Figure 2.

Figure 2 is a schematic view showing the engine, or so much of it as is necessary to an understanding of this present invention, in plan.

Figure 3 is a view showing certain joint and flame stop features of our invention.

Referring now to the drawing, the numeral 5 designates the upper and 6 the lower of two castings which together form a crank case for the engine, the two meeting in theplane of the crank shaft the front end only of which is shown.v The crank case parts meet in the plane of the crank shaft and are secured together by bolts extending through flanges as shown, and the main journals thereof (seven in the engine illustrated) are supported in bearings held in semicircular seats provided in transverse webs in the two parts of the'c'ase, as is usual in multiple cylinder engines. Only one such web, journal, and bearing is shown, the same being the front end journal I and the bearing 8 therefor. The upper half 5 of the crank case supports the cylinder blocks the farther block 9 being shown in elevation, and somewhat conventionally; whereas the nearer of the two blocks is omitted.

The front end of the crank shaft has a pinion 9 which meshes with an internal gear In carried by a flange H which drives a propeller, not shown. 'I'he periphery of this gear is cylindrical in form and rotates in a bearing I2 likewise held this application May 20,

in semi-circular seats in the crank case whereby support is' provided as close as possible to the internal teeth of the gear I; and this gear l carries an external gear [3 which meshes with a pinion which is formed integrally with short hollow journals I5, I 6 supported in bearings l1, l8 within and at the front end of the crank case member 5. The journal I 6 has internal splines which cooperate with splines upon the end of av shaft It] to drive, the same and the rear end of which is hollow and is provided with internal splines, andis supported in a bearing 20 within and at the rear end of the upper half of the crank case. The shaft l9 therefore and as will be seen extends along the crank case and is located within and close beneath the top wall thereof. An intermediate bearing 2| is also shown for steadying the central part of the shaft I 9 because of its considerable length.

The right hand or rear end of the crank case sections 5, 6 lie in a single vertical plane, and

secured to said sections through suitable flanges and bolts is an accessory housing 56 which has built thereinto the centrifugal compressor or supercharger whereby mixture is supplied to the engine cylinders under pressure greater than atmospheric pressure; and which accessory housing serves also to support various engine accessory devices such as the carburetor, the ignition magneto, the generator for the starting motor, the starting motor itself, the oil and fuel pumps, the pump for the cooling liquid and other accessories, as well also as the immediate driving means for such accessories; the housing and accessories as-' sembled therewith thus forming a single assembly independent of the crank 'case and cylinder blocks. Inasmuch, however, as this present application has to do with supercharging mechanism for the engine only such features of the accessory housing as have to do with such mechanism are shown in detail.

The accessory housing is bolted to the crank case along a plane indicated by the numeral 22; and 23 is a compressor rear wall and bearing carrying plate secured against a circular seat 24 in the housing and shaped to form the left hand wall of the air compressor, and which plate supports bearings for the driving mechanism of the rotating impeller-25 of the compressor. This impeller is carried by a shaft 26 rotatable in bearings 21, 28 carried by the plate 23 and which bearings, as will be seen, are located inside the housing 56; and between these bearings is a pinion 29 which is driven by a gear 30 upon a shaft 3|, The right hand end of this short shaft 3| is supported in a bearing 32 carried by the plate 23,. and the left hand thereof is splined and enters into the splined end of the shaft I9; so that the compressor rotor 25 is driven from said shaft 19 through the gear 30 and pinion 29. l

The outer front wall or plate 33 of the compressor is secured in place in a circular seat 34 concentric with the seat 24 and formed in the outer, wall of the housing, and this outer wall has an inlet elbow 35 formed integrally therewith and which is shown as communicating with a down draft carburetor 36 of any suitable form. The plates 23 and 33 are so shaped as to provide a chamber for the impeller 25 and a restricted passage 31 between them which passage is comparatively narrow, but of considerable length, radially, and through which the air flows from the'impeller chamber into a comparatively large annular chamber 38 surrounding the outlet from the passage 31 and merging into a large upper discharge elbow 33; both the chamber 38 and the elbow being parts of the housing 56 and the whole being secured to and supported from the rearend of the crank case 5, 6 as hereihbefore explained. v

The plates 23 and 33 form an air passage from the carburetor 36 to the elbow 39, and they are secured in seats in and form a part of the accessory housing which housing, however, is not disclosed in detail'as this present invention does not relate particularly thereto. The restricted passage 31 between the high pressure discharge of the compressor and the comparatively large space provided by the air chamber 38 and elbow 39 provides a construction which equalizes the discharge from the compressor, and in which surges I of air are avoided and a more uniform pressure in the chamber 38 and flow of mixture therefrom and throughout the supply manifold system and to the engine cylinders is secured, than in mixture supply systems heretofore in use.

Arranged in the inlet passage leading from th carburetor to the air compressor 25, and located as close as possible to the inlet thereof, is a stationary vane member comprising a central coneshaped hub 4|! and a series of radial vanes 4! extending therefrom to a peripheral ring 42, which is seated in a recess provided in theouter wall or plate 33.

The stream of combustible mixture which flows through the elbow 33 is divided into two parts by a hollow connector 43 arranged adjacent the rear end of the engine, one part thereof flowing onward and upward through 'a short passage or conduit and into a transverse conduit' 44 wherein it is divided again, half going to the three rear cylinders of the farther block and half to the three rear cylinders of the nearer block. The second part of the mixture flows onward from the connector 43 through a conduit-45 and upward into a second transverse conduit 46 wherein it is likewise again divided, half going to the three front cylinders of the farther block and half to the three front cylinders of the nearer block.

The transverse conduit 44 leads into headers cylinders of the engine, each header supplying three cylinders of an engine block.

The conduit 46 leads into headers 49, 50 for the six forward cylinders which headers are identical with those above described, and act in the same way to supplj mixture to said forward cylinders; from which it follows that each group of three cylinders derives its supply from one single header, and that the supply to each group of three is isolated from that of other groups, thus securing a more uniform distribution of the mixture to the cylinders than would be the case were a larger number than three to derive their supply from a single header or like immediate source. Variations in suction in any particular header due to the cylinders which it supplies not being identical with other groups of cylinders, or due to temporary irregularities of operation of such cylinders, or to other causes, will therefore not be communicated-to other headers or if communicated will be communicated to but a slight extent. Irregularities of operation of one of the three cylinders which any particular header supplies will to be sure affect the operation of the other two, but the effect of any such irregularity will be limited mostly, and indeed substantially entirely, to the three cylinders supplied by the header in question.

The entire supply manifold system is located in the V-shaped space between the cylinder blocks,

and its construction is obviously such that the flow of the mixture is uniformly upward and to.- ward the engine heads, the one of the farther block being indicated by the numeral 5|. The manifold system is provided with expansion joints at various places where parts thereof are joined together, one of such joints being shown in section in Figure 3; and back-fire preventing screens 52 of any suitable type are secured in place at these joints as shown in said figure. In the form of our invention illustrated such flame stops are contemplated also at the joints 53 and 54, their purpose being to prevent the ignition of the mixture in the compressor and carburetor should the mixture in the headers, as is often the case, be ignited by backfires from the engine cylinders.

The numeral 51 designates a heating jacket arranged between the carburetor 36 and the inlet into the mixture compressor for heating the combustible. mixture, and through which hot liquid taken from' the cooling system of the engine is caused to flow by the use of suitable pipes not'shown.

The shaft. l9, as will be appreciated, is comparatively long, and its diameter is preferably reduced intermediate its ends as shown. This feature of a long and slender driving shaft provides torsional flexibility in the driving mechanism for the impeller of the centrifugal compressor, and very materially reduces the transmission of torsional vibrations commonly present in crank shafts of multiple cylinder engines to the rotating impeller of the centrifugal compressor, which is ordinarily driven at a speed considerably above that of the crank shaft and should be driven at a uniform speed. The torsional resiliency inherent in the long and slender driving shaft for the impeller secures the driving thereof without shocks, and a smoother running impeller than would otherwise be the case.

This present application is a division-of our an outlet which communicates with a conduit;

syst'emwhereby combustible mixture is supplied to the cylinders of the engine; a shaft extending longitudinally of the engine and throughout the length of the crank case thereof, and which shaft is rotatably supported in bearings at the ends of said crank case; gearing at the front end of the crank case for driving said shaft;

andvmeans whereby the impeller shaft of said compressor is driven from the rear end of said longitudinally extending shaft.

2.-In supercharging mechanism for multiple cylinder internal combustion engines, a housing separate from the crank case of the engine and secured to the rear end'thereof a centrifugal compressor associated with said housing and the shaft of the impeller of which is rotatable in a bearing'device located within said housing, said compressor having an inlet leading thereinto, and an outlet which communicates with a conduit system whereby combustible mixture is supplied to the cylinders of the engine; a shaft extending longitudinally of the engine and throughout the length of the crank case thereof, and which shaft is rotatably supported in bearings at the ends of said crank case; gearing at the front end of the crank case for driving said shaft; a short shaft with which the rear end of said longitudinally extending shaft is operatively connected; a bearing within said housing and whereby the extremity of said short shaft is supported; and gearing whereby and through which the impeller shaft of said compressor is driven by said short shaft.

3. In supercharging mechanism for multiple cylinder internal combustion engines, a housing separate from the crank case of the engine and secured to the rear end thereof; a centrifugal compressor associated with said housing and the shaft of the impeller of which is rotatable in bearings within said housing, said compressor having an inlet leading thereinto, and an outlet which communicates with a conduit system whereby combustible mixture issupplied .to the cylinders of the engine; a shaft extending longitudinally of the engine and throughout the length of the crank case thereof, and which shaft is rotatably supported in bearings at the ends of said crank case; gearing at the front end of the crank case for driving said shaft; a short shaft arranged in line with said longitudinally extending shaft, and means for providing a splined driving connection between said two shafts; a bearing within said housing and whereby the extremity of said short shaft is supported; a gear carried by said short shaft; and. a pinion trifugal compressor;

upon the impeller shaft of the compressor with which said gear meshes to thereby drive said impeller. I

4. In supercharging mechanism for multiple cylinder internal combustion engines, a housing separate from the crank case of the engine and secured to the rear end thereof; a compressor rear wall secured in a seat provided in said housing, and having two bearings spaced apart from "one another for supporting the shaft of a cena compressor front wall secured in a seat provided in said housing and having an inlet, said walls being shaped to provide an impeller chamber and a narrow passage leading therefrom into an enlarged annular chamber surrounding the outlet' from said narrow passage; a discharge member associated with said housing and through which mixture flows from said annular chamber; a rotary impeller within said impeller chamber and the shaft of which is supported in the bearings aforesaid; and means for driving said impeller shaft from the front end of the engine.

' 5. In supercharging mechanism for multiple cylinder internal combustion engines, a housing separate from the crank case of the engine and secured to the rear end thereof; a compressor rear wall secured in a seat provided in said housing, and having two bearings spaced apart from one another for supporting the shaft of a centrifugal compressor; a compressor front wall secured in a seat provided in said housing and having an inlet, said walls being shaped to provide an impeller chamber and a narrow passage leading therefrom into an enlarged annular chamber surrounding the outlet from said narrow passage; a discharge member associated with said housing and through which mixture flows from said annular chamber; a rotary impeller within said impeller chamber and the shaft of which is supported in the bearings aforesaid; a short shaft the extremity of which is supported in a bearing carried by said compressor rear wall;

intermeshing gears whereby said short shaft is arranged within thespace between said cylinder blocks and communicates with all of said cylinders so as to supply combustible mixture to all of them; a centrifugal compressor arranged at one end of said blocks whereby combustible mixture is supplied to said system; gearing driven by the crank shaft of the engine arranged at the other end of said blocks; and a longslender shaft driven by said gearing and adapted to drive the impeller .of said compressor,

Whereby torsional vibrations of said crank shaft are absorbed by said long shaft.

HAROLD CAMINEZ. NORMAN H. GILMAN.

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