US1703718A - Multicylinder two-stroke-cycle internal-combustion engine - Google Patents

Description

'- E. BROWN IULTICYLINDER TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE Filed April 15, 1926 2 Sheets-:Sheet 1 Fly, 2.

uremia" M? M [I Febrzs, 1929.

E BROWN IULTICYLINDER TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE Filed April 15, 1926 2 Sheets-Sheet 2 II I I I m I a I II I :22 Ix .v m ri v v mmfo;

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Patented Feb. 26,1929.

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'mumrmmbnn rwo-smoxn-cxcm INTERNAL-COMBUSTION nnenm Application iued awu 15, 1924 Serial 80.1%,878, and in Germany m 11, 19:5.

Thege'neral object of the invention is the provislon of means for the purpose of enabling. the exhaust and supervening scavenging operations in each cylinder to take place truly concentrically with the cylinder axis.

Another object of the invention is to free the cylinder liner of heat stresses resulting from the difference in temperature be- 7 tween the adjacent. belts of ot exhaust gases andcold scavenging air surrounding the liner; I

Other and further objects of the invention will be pointed out or indicated hereinafter or willbe apparent to one skilled in the art upon an understanding of the invention or its employment in practice.

In the accompanying drawings forming part of' this specification Ii illustrate in diagrammatic fashion various arrangements 1n which .the invention may be embodied, but

it is to be understoodthat the invention as defined in the claims is not to be construed as limited to any of these illustrative forms. In the drawings 2- Figure 1 is a section along 1-2 of Figure 2;

Figure 2 and I Figure 3 a section alon 5-6 of Figure 1 of an applieation'of the invention to a single acting engine; Figure 4 is a section a section along 34of Figure 1,

along 16 -17 of Figures 5 and 6;

forms of port on an enlarged scale.

Two-stroke cycleinternal combustion eng ines of the type referred to have many advantages, among which are e 1. maximum cross sectional area of port becomes available immediatel the ports are uncovered owing to, the uti ization of the whole eriphery of the cylinder bore.

J 2. ,T e formation and maintenance of eddying bodies of inert gas during the scavengin operation is avoided.

1 3. he ened.

4. The part of the stroke during which path of the scavenging airis Shortthe ports are operated is reduced to a min-' imum; andvv v 5. The heatstresses and expansions due to heating of the cylinder, iston and piston rod as far as these are a ected by the flow of exhaust gases and scavenging air are perfectly symmetrical with the cylinder axis.

In order to obtain these advantages to the full extent itis necessary that the exhaust and scavenging operations shall take'place truly concentrically with the cylinder axis,

as otherwise there will be one-sided exhaust andscavenging currents which defeat the object aimed at. It is a condition, therefore, that the pressure behind each exhaust port and the pressure in frontof eachair scavenging port shall each remain ap roximately completely balanced during t e operations in question.

The .object of the present invention is to provide means for fulfilling these conditions, that is to effect these pressure equalizations in-a technically perfectrmanner in multicylinder two-stroke internal; combustion engines of the port exhausting and scavenging type referred to. 5 r

' According to this invention these means consist'inconnecting the exhaust ,ports "to two exhaust passages or manifolds, that are located one on either side of the row of cylinders with respect to a plane passing through 'the rshaft and cylinder axes, and that thescavenging air ports are fed from two air supply passages, that are likewise located one on either side of the row of c linders with res ectto a lane. ass" through the shaft f ind'cylind r In this way technically detrimental differences in pressure behind the exhaust ports and in front of the scavenging v 1 are prevented, as the exhaust gases-01:. t

4O *-21whereby 'a perfectly unobstructed 7 are exhaustports distributed over the entire periphery of the cylinder bore and uncovered by the-piston at the end of the power stroke and 8 are scavenging ports also distributed around the entire periphery. The exhaust passage is divided into two halvesl and 10 Which are placed at either side of the engine symmetrically to the plane 11 -42 passingthroughthe shaft and cylinder axes. By this means in spite of: the

distance betweenthe'cylinders' namely 13 of'FigQ plus 13 of Fig. 3 being smallthe pressureis equalized behind the outlets of the exhaust ports sufliciently for obtaining true axially concentric scavenging. For correct functioning it is essential thatthe extensions ofthe exhaust passages 9 and '10 as'far as their-junction with one another or as Iar aswhere they pass to the outside shall each offer the same resistance to the flow. Simicentric scavenging.

larly, the scavenging air passage is divided into two parts i lv and .15, whereby the air,

pressure in front scavenging ports- 8 leading from the passages 14k and. 15, 111 wh ch there is the same pressure, is equahzedas far as isrequired to ensure true axially con- I In Figures 4, 5 and 6 a row of double acting cylinders are shown, each cylinder'half "otwhich exhausts into a pair of exhaust ,mani- folds 22, 23 and 24, 25 respectively,

. which manifolds are so arranged that a zone 26 isformed' on either side oi the plane 7 wide space isproduced, which 'islaterally I bounded'by the walls 27, 28, 29,30 and to which; is'supplied through p1pes31, 32,

the"'scavenging air pump. In the ex;-

ample shown the exhaust passages are made I the-form ofboxes" into which the cylinders or their liners 33,34 extend andfare 7 fixed by means of their flanges 3.5, 36.

.In order, to allow for the relative axial L expansion Qof and 'relief of heat stresses in theicylinder liners, due to the proximity of theubelts of hot exhaust gases and cold scavenging air around these entire peripheries, they are the example divided intoithree sections 33, 3,7, 34-, whereby the inner ends Q of the. two outer sections 33 and 34' are crenelated and the teeth so formedf 'are adapted to slide axially and subsstantially' gas tight in the gaps between teeth formed bylcrenelations ateither end of the middle section 37, so that; when the teeth are'in engagement the gaps in the outer sections 1 form the exhaust ports '38, 39 and? the gaps mas middle section the scavenging ports cylinder thus forming by their engagement both the exhaust and the scavenging air ports. i

The middle section 37 of the cylinder linings 'may act'as centering and distancing members between the exhaust boxes 22-23 and 24 -25. For this purpose they-are provided with projecting parts d6, with axial abutment surfaces 47'48 and with cylindrical centering surfaces 49 50. The whole is. held together and fixed to the frame of the engine by 'means of bolts 51' extending right tl1rough the difierent parts.

The ends of the exhaust ports 52-53,

where they open into the collecting exhaust passages 22-23 may be formed like deflecting blades, so as to prevent the formation of eddies and to assistthe flow of the exhaust on either sideby suction.

"In the case of internal combustion engines of large dimensions the collectin exhaust passages 2223 may be bolted on laterally. 1 i i Preferably the middle section 37 of the cylinder lining is'cooled by scavenging air only.-;, The teeth'54 between t the exhaust ports if at all are preferably cooledby means of tubes 55 extendingv into them, through which the water for thecooling jacket flows in or out. For this purpose annular ducts 56, 57 andconnecting branches 58, 59' are provided at the cylinder ends. The cooling water is preferably distributed to the tubes 55'by bafiies.

.What I claim is i 1. A two-stroke cycle internal combustion engine having "in combinationa plurality of cylinders, exhaust ports substantially uniformly-distributed around the periphery of each of said cylinders, scavengingair ports uniformly distributed around the periphery of e'achbf said cylinders, working. p stons uncoyeringsaid exhaust and scavenging air ports and covering same in opposite order,

40, 41 around the entire periphery of the a plane. substantially commonto the axes of said cylinders,two exhaustpassages common to: said cylinders and, arrangedfone on each side of said plane, communicationpassa'ges between the exhaust ports of each of said cylinders and each of'said' exhaust passages, two scavenging'air passages common to said cylinders and arranged one on eachside of said plane, and communication passages between said scavenging air ports of each of said cylinders and eachofsaid scavenging air passages. V 1 V 2. A two-stroke cycle internaljcombustion engine having in combination a plurality of double acting cylinders, exhaust ports substantially uniformly distributed around the periphery of each working end of each of said 'cyl1nders',,scavenging air ports substantially uniformly distributed" around the'periphery of each working end of each of said to the working ends of said cylinders, and

a communication passage between said scavenging air ports and said scavenging air passages.

3. A two-stroke cycle internal combustion engine having in combination a plurality of double acting cylinders, each cylinder divided into three aligned portions, each said portion interengaging in axial slidable crenelations of the abutting portion, axial gaps between tips of the interengaging teethiof the centre portion and the roots of the teeth of said external portions of said cylinder forming exhaust ports substantially unieach working end of each of said cyh peripherg of n ers, axial gaps between the roots of the interengaging teeth of the centre portion and the tips said cylinder forming scaven substantially uniformly distributed around formly distributed around the the periphery of each working end of each of said cylinders, a double acting piston in each of said cylinders uncovering said exhaust and scavenging air ports and covering same in opposite order, a plane substantially common to the axes of said cylinders, four exhaust passages pairwise common to each working end of said cylinders, one pair on each s1 e of said plane, communication pasthe teeth of said external portions of ging air ports 1 sages between said exhaust ports and said I I exhaust passages, two scavenging air passages of whlch one is on each side of said plane and common to the working ends of said cylinders, and a communication passage between said scavenging alr ports and said scavenging air passsages.

In testimony whereof I have signed my name to this specification.

ERIC BROWN.

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