US2031318A

US2031318A - Engine

Info

Publication number: US2031318A
Application number: US406090A
Authority: US
Inventors: Junkers Hugo
Original assignee: Firm Junkers Motorenbau G M B
Current assignee: Firm Junkers Motorenbau G M B; FIRM JUNKERS-MOTORENBAU GmbH
Priority date: 1928-11-20
Filing date: 1929-11-09
Publication date: 1936-02-18
Anticipated expiration: 1953-02-18

Description

H. JUNKERS Feb. 18, 1936.

`-ENGINE Filed Nov. 9, 1929 Patented feb. 18,

. ENGINE cHugo Junkers, Dessau, Germany, assigner toI My invention refersztoiengines and more especially to the kind of engines in which two pistons are arranged in'each cylinder for reciprocation in opposite directions, these pistons acting ontwo separate crank shafts, one at each endof the plston,fwhich are positively coupled with each other by means of suitable. gearing, such as toothed wheels, chains, crank gear, orthe like.

If the power generated by th engine is transmitted only by one Aof these shafts or by a part of the intermediate gearing adjoining one of the shafts, these gears are called-.up on to transferV that half of the output, which is transmitted by the second shaft, towards the first `crank shaft, `and. are therefore required to be comparatively heavy and large, so that considerable losses of power are incurred.

The present invention contemplates a considerable reduction of the percentage of power tobe transmitted from the intermediate gearing ltothe place ofconsumption, in order to effect a saving of space, weight, cost, and power4 losses.

To this end I employ means well known per seY for making the percentage of work to be transmitted by each of the two crank shafts unequal and I cause the major portion of the engine output to be taken oif the more heavily loaded shaft, or if the intermediate gearing has the form of" a toothed wheel gearing with a plurality Vof intermediate wheels arranged 'in series, from the axle of the toothed wheel directly adjoiningthis shaft. I thereby obtain that the power to be transmitted by the intermediate gearing is less firm: Junkers-Motorenbau Germany G. m. b. H., Dessau,V

Application November 9, 1929", serial No. 406,090

Germany November 20, 1928 than one half of the total power.

Inbrder to obtain'an unequal .distribution of work onto the two crank shafts, I may for instance use the following means: l

(a) In internal combustion engines, the cranks of .those pistons, which transmit the major amount of power, are made to lead the cranks of the pistons transmitting the minor amount of power.

(b) Pistons ployed;

In the drawing amxed to' forming .part thereof. twol modications of an engine embodying my invention are illustrated diagrammauesuy by way' In. the drawing of example.

different strokesare ema.

(c) That crank shaft receiving thel minor amount of power is ,utilizedl for operating the auxiliary, devices to be-driven by the engine, such as for instance the pumps for cooling water, combustion air, f fuel,` lubricant, etc., the electrical this speci-ca'tion and Fig. 1 is a diagram which illustrates the unequal distribution of the output, which. results in an internal combustion engine with double pistons from the leading of the crank for the exhaust piston.

Figs. 2 and 3 are an axial longitudinal section `and an axial cross section, respectively, of the first,i and v Figs. 4 and 5 are similar views of the second modification.

Fig. l illustrates thev pressure-volume-diagrams corresponding to the` thrust of an internal combustion engine having two pistons operating in opposite directions, the cranks of these pistons u relative to their extreme positions. The dla.-

' gram surface bordered by the curved line I corresponds to the percentage of. power which is transmitted to the piston controlling the exhaust ports, which is connected with the leading crank. 20

The surface bordered by the curved line 2 corresponds to thg percentage of power transmitted by the piston controlling the scavenging ports, this latter percentage being considerably lower than the one transmitted by the iirst mentioned 25 piston. The relation between the two characteristics and the angle of lead d can easily be guessed from the diagram. i n

Referring now to Figs. 2 and 3, I0 area plurality of juxtaposed cylinders, and II, I2` are two` 30 pistons arranged in each cylinder for reciproca.- tion in opposite directions. I3 are the intake ports for the scavenging air or mixture arranged f-at one end of the working chamber of each cylinder. opposite end. of the working chamber. The pistons vI I controlling the scavenging ports I3 transmit power yto the crank shaft l5, the pistons I2 controlling the exhaust ports operate the crank shaft I6. The two shafts are positively con- 40 nected with each other by bevel gearlngs I'I,y I8, and I9, 20, respectively, and an intermediate shaft 2l in such manner that each crank of shaft IB leads with regard to the crank, belongingi'to the same cylinder, of lshaft I5 by a predeter- 45 mined angle a (Fig. 3). 'Ihe power generatedV by the engine is transmitted for instance to a water or air propeller 23 driven by the engine by means of an extension 22 of the crank shaft I6 arranged on the exhaust side. In consequence of `this ar- 50 rangement shaft I6 is acted upon with more than one half of the engine output, and in consequence thereofl the intermediate gearing I1 to 2| is not called upon to transmit one half, but less thanv onehalfofthetotaloutrmt; Inordertofun-gg being staggered through alpredeterminedangle 15 I4 are the exhaust ports arranged at the 35 ther reduce the power to be transmitted by this gearing, the auxiliary devices 30, 3|, to be opercrankshaft I5'. 'I'he two crank shafts are positively coupled by toothed wheels I1', I8', I9', 20', arranged in series, in such manner that the crank l shaft rI6' leads with respect to the shaft ISby an angle a, whereby also an increased transmission of power to shaft I6' is obtained. In order to further increase the percentage of power transmitted to shaft I6', the radius of the cranks oi shaft I6 is made longer than theI radius of the cranks of shaft I5. Here power is transmitted by means of the extension 25 of the axle of the intermediate wheel 20' directly adjoining crank shaft I 6', so that only this intermediate wheel is more heavily strained, while the other intermediate wheels Il' to I 9' are much less loaded. According to the diameter of the toothed wheels 2i'- and 22' mounted on the crank shafts and of the intermediate wheel 20 transmitting power, an increase or reduction of the number of revolutions can be obtained for the power transmitting axle 25 with iespect to the crank shafts. Auxiliary devices 38', which are to be operated by the engine, are here again connected to the crank shaft I5'. Y

The most advantageous embodiment of my invention, comprises a twin-shaft, two-cycle internal combustion 'aeroplane engine, a plurality of juxtaposed cylinders having intake and exhaust ports, a pair of crank-shafts one mounted at each end of-said cylinders rotating at the same speed, a pair of pistons mounted to reciprocate in each of said cylinders in opposite directions and operatively connected by means of crank arms to transmit power to said crank-shafts, one of said pistons being adapted to control said intake ports and the other being adapted to control said exhaust ports, means including crank arms of unequal crank throw producing an unequal distribution of power to said crank-shafts; the crank arms having the greater crank throw transmitting the major amount of power; a driven part `coupled to both crank-shafts, and means for synchronizing the operation of said crank-shafts and for transmitting power from the crank-shaft receiving the minor amount of power to said driven part, said synchronizing means being of such weight and strength as to be adapted to transmit less thanvhalf of the total power delivered' to said driven part, the crank-shaft receivingthe major amount of power being more closely coupled to said driven part than said shaft receivingof power, I mean that the former shaft is 'closer to the driven part or is coupled therewith more directly or through fewer moving' parts or through ore sturdy mechanism.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in theart.

1. In a twin-shaft', two-cycle, internal combustion engine, a plurality of juxtaposed cylinders having intake and exhaust ports, a pair of crankshafts one mounted at each end of said cylinders rotating at the same speed, a pair of pistons mounted to reciprocate in each of said cylinders in opposite directions and operatively connected by means of cranks and crank arms to transmit power to said crank-shafts. one of said pistons being adapted to controlA said intake ports and the `other being adapted to control said exhaust ports, means 'including leading and lagging cranks producing an unequal distribution of power to said crank-shafts, said leading cranks, beingconnected to the crank-shaft receiving the major amount of power. a driven part coupled to both crank-shafts, and means for synchronizing the operation of said crank-shafts and for transmitting power from the crank-shaft receiving the minor amount of power 'to said driven part, said synchronizing means' being of such weight and strength as to be adapted to transmit less than half of the total power delivered to said driven part, the crank-shaft receiving the major amount of power -being more closely coupled to said driven part than said shaft receiving the minor amount of power.

2. 'I'he engine of claim 1 wherein the driven part is mounted on the crank-shaft receiving the major amount of power.

3'. The engine of claim 1 wherein said crankshaft receiving the minor amount of power is coupled to more auxiliary machinery than said crank-shaft receiving the maior amount o power. r

4. 'I-'he engine of claim 1 wherein said vsynchronizing means comprises a train of gears, the driven member being mounted on one of the shafts of said gears.

' HUGO JUNKERS.