US2669979A - Reed valve unit for crankcase induction engines - Google Patents

Description

1954 E. G'KIEKHAEFER 2,669,979

REED VALVE UNIT FOR CRANKCASE INDUCTION ENGINES Filed Sept. 11, 1950 2 Sheets-Sheet l INVENTOR.

Feb. 23, 1954 K HA R 2,669,979

REED VALVE UNIT FOR CRANKCASE INDUCTION ENGINES Filed Se t.) 11, 1950 2 Sheets-Sheet 2' M i-um m /5 i s 1N VEN TOR.

filo/ways Patented Feb. 23, 1954 UNITED STATES PATENT OFFICE REED VALVE UNIT FOR CRANKCASE INDUCTION ENGINES Elmer CJKiekhaefer, Cedarburg, Wis.

Application September 11, 1950, Serial No. 184,242

9'Claims.

This invention relates to crankcase induction valve means for two-cycle, internal combustion engines, and particularly two-cylinder, alternate firing engines.

The invention provides a crankcase induction reed valve unit which admits and directs the fuel mixture into the crankcase in streams directed radially from and arranged about the crankshaft passing through the crank chamber.

A principal object of'the invention is to provide a reed valve unit which will admit reater fuel charges more efficiently into the crank chamber.

i A further object is to provide a valve unit of maximum volumetric capacity without necessarily increasing the volumetric capacity of the crank chamber to accommodate the valve unit.

Another object is to provide a more efficient arrangement of the reeds with respect to the crank chamber of an engine.

A more particular object is to admit the fuel mixture into the main part of the crankcase chamber in the most direct manner whereby the engine will receive a greater amount of fuel charge with each stroke.

These and other objects and advantages will be more fully set forth ,in the following description of a preferred embodiment of the invention as illustrated in the accompanyin drawings.

In the drawings:

Figure 1 is a perspective View of the split bearing block adapted to support the center main bearing of an engine crank shaft and showing the passages as formed therein for the crankcase induction system of the engine;

Fig. 2 is a plan view of the joined block showing the reed sections and rocker arms therefor as arranged on one face of the block;

Fig. 3 is a view taken on line 3-3 of Fig. 2 showing the mating surface of one of the members of the bearing block;

Fig. 7 is a cross-sectional view of atwo-cycle.

alternate firing, two cylinder engine employing crankcase precompression with one piston cut away to show the intake ports and employing the open position and reed valve-center bearing block shown in Figs. 7

lto4;and 4,

Fig. v8 is a. horizontal transverse section of the engine shown in Fig. 7 viewing the valveblock I in plan as shown in Fig. 2.

The engine shown in the drawings includes the I cylinder block I and member 2 which join in a transverse plane passing through the axis of the engine crankshaft 3. Crankshaft 3 1s supported at each end in the journal'bearing as-' semblies 4 which close the opposite ends of the generally cylindrical crankcase 5 formed jointly.

Crank throws 9 and ID are spaced with respect to the crankshaft axis so that the pistons reciprocate in opposite directions for alternate firing or with each 180 of crankshaft rotation.

Crankcase 5 is divided into the separate upper and lower crank chambers II and 12 by the bearing block [3.

In the two-cycle operation of the engine, the.

fuel mixture is admitted into the cylinders through the corresponding passages I4 in the side of cylinder block I. Each passage l4 communicates with the respective crank chamber and opens through ports l5 into the respective cylinder bore 6. The exhaust gases are discharged through opposite ports 16 opening from each cylinder bore into suitable exhaust means,

not shown. The intake and exhaust ports of each bore arecontrolled by the respective piston which opens the ports at the lower end of each piston stroke and otherwise closes the ports during the compression and power stroke.

The precompression of the fuel mixture for transfer of the mixture through passages [4 to the respective cylinder and to displace the exhaust gases remaining in the fired cylinder is.

effected with each crank chamber by'the corresponding piston during the downward powe stroke.

The two complementary, semi-circular bearing. members I! comprising block, l3 are joined by bolts 18 passing therethrough on each side of a central axial bore l9- as shown in Fig. 3. Bore I9 is adapted to fit the center bearing 20 of crankshaft 3 between crank throws 9 and ID for:

the journal support of the crankshaft. The outer d1mension of members. I! fit the corresponding machined inner surfacesv of crankcase 5- to divide the latter into chambers H and [2.

The induction manifold passages 2| in memhers I! jointly registerwith the opening22 in}: crankcasemember 2; The carburetor 23 secured the opposite end of each reed being angularly disposed to deflect the fuel mixture passing through said ports radially of said crankshaft andagainst the adjacent wall of said chamber.

3. In a two-cycle, internal combustion engine having a crankshaft and a crank chamber receiving a fuel mixture for precompression, said chamber being substantially cylindrical and hav ing a circular end wall spaced from the crank and normal to the axis of crank rotation, a series of ports opening into said chamber from said end wall for the delivery of fuel mixture thereto, and a series of flexible reeds having a common circumferentially extending base strip secured upon said end wall, each reed extending radially from said strip over a respective port normally closin the latter and being disposed to be lifted from said end wall toopen said port and to deflect .the fuel mixture entering said chamber against the side walls of said chamber adjacent the end wall thereof and around the crank into the center of the chamber.

4. In an internal combustion engine having a crankcase forming a crank chamber for induction and precompression of the fuel mixture, a crankshaft having a crank throw and a journal bearing supporting said throw, said crankcase having an end wall adjacent the crank throw and spaced therefrom and including a complementary bearing supporting said crankshaft bearing and having a side wall extending from said end wall about said crank throw, a fuel induction passage formed in said crankcase having a series of ports opening in said end wall, said ports being arranged about said bearing and opening towards said crank throw, valve reeds fixed at one end to said end wall and having a free opposite end, the fixed ends of said valve reeds being adjacent said bearing and the free end extending toward the side wall of the crankcase, said reeds being normally seated over said ports on said end wall and subject to flexing to open said ports and allow the entry of fuel mixture therethrough into said chamber, the opposite end of each reed being angularly disposed to deflect the fuel mixture passing through said ports against the adjacent wall of said chamber, and radially arranged arms secured to said end wall and projecting over each of said reeds to limit the flexing of said reeds.

5. In a two-cycle, internal combustion engine having a crankshaft and a crank chamber receiving a fuel mixture for precompression, said chamber being substantially cylindrical and having a circular end wall spaced from the crank and normal to the axis of crank rotation, a series of ports opening into said chamber from said end wall for the delivery of fuel mixture thereto, a series of flexible reeds having a common circumferentially extending base strip secured upon said end wall, each reed extending radially from said strip over a respective port normally closing the latter and being disposed to be removed from said end wall to open said port and to deflect the fuel mixture entering said chamber against the side walls of said chamber adjacent the end wall thereof and around the crank into the center of the chamber, and a circumferentially extending member secured to said end wall over said base strip and having a radially projecting arm extending over each of said reeds to limit the movement of said reeds.

6. In an alternate firing, two cylinder internal combustion engine having a crankcase for .in-

cit

duction and precompression of the fuelmixture, a crankshaft having spaced crank throws and an intermediate journal, a split bearing member assembled on said journal and dividing said crankcase into corresponding crank chambers having side walls extending from said bearing member about said crank throws, a fuel induction passage formed in said bearing member having a series of ports opening therefrominto said chambers, said ports being arranged about said journal and opening towards the crank throws, and valve reeds having ends fixed to said bearing member, the fixed ends of saidvalve reeds being adjacent said journal and the free end extending toward the side walls of the crank case, said reeds being normally seated over said ports on said member and subject to flexing to open said ports and allow theentry of fuel mixture therethrough from said passage into the respective chamber, the free end of each reed when flexed being angularly disposed to deflect the fuel mixture passing through said ports radially of said crankshaft journal and against the adjacent wall of the respective chamber.

'7. In a two cylinder internal combustion en-' gine having a crankcase, a crankshaft having spaced crank throws and an intermediate bearing supporting said throws, complementary bearing support members for said crankshaft assembled thereon and disposed to divide said crankcase into corresponding crank chambers for induction and precompression of the fuel mixture, a fuel induction passage formed in said members and a series of ports opening into each of said chambers, said ports being arranged about said bearing and opening towards the corresponding crank throw, valve reeds fixed to said members, the fixed ends of said valve reeds being adjacent said bearing and the free end extending toward the side wall of the crankcase, said reeds being normally seated over said ports on said member and subject to flexing to open said ports and allow the entry of fuel mixture therethrough into said chamber, the opposite end of each reed when flexed being angularly disposed to deflect the fuel mixture passing through said ports against the adjacent wall of said chamber, and radially extending fixed arms secured to said member and projecting over each of said reeds to limit the flexing of said reeds.

8. In a two cylinder, two-cycle, internal combustion engine having a crankshaft and a crankcase therefor receiving a fuel mixture for precompression, complementary journal bearing members assembled on said crankshaft to support the same and disposed to divide said crankcase into separate crank chambers for the respective cylinders, each member having a fuel supply passage and opposite faces forming an end wall of each chamber, a series of ports in each member opening into each of said chambers from said passages for the delivery of fuel mixture thereto, a seriesof flexible reeds having a common circumferentially extending base strip secured to each face of each member, each reed extending radially from said strip over a respective port normally closing the latter and movably disposed to open said port and to deflect the fuel mixture entering the respective chamber against the walls of said crankcase into the center of the chamber, and a circumferentially extending member secured to each of said members over each of said base strips and having a radially projecting arm extending over each of said reeds to limit the movementof said rods.

9.. In an; alternate, two:

combustion engine having a. crankcase icmindtm tion and preeompression oithe fuel mixture, a crankshaft having spaced crankthmws: and intermediate journal, a v split. hearing assembled on said: journal and dividing saidv crankcase into corresponding chambers having, side walls extending from sai dashearing member about saidi craniethrows, a secured toy and exteriorly of saideranhdase adjan; cent said. member, fine]: induction passages formed. in said bearing; member having a series ofports opening therefrom into said chambersgid ports being; arranged about said vjournah' and: opening towards? the crank: throws, said crank: case having an opening; firomg said: carburetor and: extending circumferentiaily' of: said member an extended distance, opposite directions td some mnnioate with the passage thereof: and provide f f the u l mixtur di ect y toiia number 202 of adjacent ports, and val-yes reeds hamends fixed to said bearing member; thefixed ends of tid 1 be ng idiacent said journal and.

the e nd e e d n toward theidewalls of the; crankcase, said reeds being normally; seated 2 8; over-said ports. on. said member and: subject to flexing. to open said ports and ailow the entryofi fuel mixture theret-hrongh from said passage into the respective chamber; the free end or each read when flexed beingangularly disposed to deflect: the. iueI mixture passing through said ports radially of said crankshaft journak and against the adjacent wail of the respective chamber.

ELMER C:

References Cited in the file. of this; patent STATES PA'IEN'I'S'

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