US1570914A - Starting mechanism for internal-combustion engines - Google Patents

Description

Jan. 26 1926. 1,576,914

F. MULLER STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES I Filed March 25. 1921 g sheets-sheet 1 Jan. 26 1926. 1,570,914

I F. MULLER STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed March 25 1921 2 Sheets-Sheet 2 Patented Jan. 26, 1926.

UNITED STATES PAT FRIEDRICH MULLER, OF VIENNA, AUSTRIA.

STARTING MECHANISM FOR INTERNAL-COMBNSTION ENGINES.

Application filed March 25, 1921. Serial No. 455,575.

(GRANTED mm. m raovrsrons or rlm ACT crimson s, 1931, 41 su'r. 1.,1818.)

To all whom it may concern Be it known that I, FRIEDRICH Mt'ILLnR, a.

anism for Internal-Combustion Engines (for which I have filed applications for patents in Austria June 23, 1915, November 16, 1916, November 16, 1916, and May 4, 1918, and applications for patents on saidinvention wereduly filed in Germany, Norway, France, Denmark, Sweden, Hungary, Czechoslovakia, and Switzerland), of which the'following is 'a specification.

It has already been proposed. to facilitate the starting of internal combustion engines by removing or reducing the compression resistances occurring during the compression strokes, by opening air escape means in the working cylinders. As soon as the first 1gnitions occur or the flywheel has gained enough momentum for the engine to be able to overcome the compression resistances, the

normal compression is put in operation for all the cylinders and the engine is in running order. In the case of multicvlinder engines the drawback is frequently met with, that. on passing from the decompression to the full compression. a number of compression strokes have to be overcome immediately one after another, for overcoming which the starting means are not suificient. The en-- gine stops and the next starting is still more ditficult than the previous one, when the starting medium is already partly used up or exhausted.

The present invention relates to a method, by which this drawback is overcome. The method consists in this, that in the case of multicylinder engines the passing to the normal compression is effected not for all the working cylinders at the same time, but gradually for the separate cylinders. Thus,

for instance, according to the invention, only one cylinder is brought up to the full "compression and, on the first ignition or combustion taking place in this cylinder, the second cylinder is brought up to the full compres-' sion stroke etc. The method according to the invention is carried, out in such a manner that the. air escape means provided on ,the working cylinders are opened during a por-' tion of the compression stroke or are held open during the whole starting period and.

that these means are closed one after another, singly or in groups, in a suitable sequence, on the separate cylinders passing to the normal compression.

' The method is suitable more particularly for multlcylinder Diesel engines, -which in consequence of the high compression pressure have a very great starting resistance. In this case the starting is difiicult for this reason that, on partial compression. taking place, there w1ll be no combustion and that the overcoming of the compression resistance must be efl'ected entirely by the source of energy available for putting the engine in 013819131011. The possibility to cause at first a combustlon in one single working cylindel only, while in the other cylinders the resistances are cut out, and thereupon to let the other cyhnders start in suitable sequence ensures a very rational and safe starting with a mlnlmum waste of energy. Hence, the invention represents an important improve ment in such engines. 1 Fig. 1 is a longitudinal Vertical 'sectiona VIEW. through a four-cylinder engine and on the hne of the main and the cam shafts;

F1g. 2 1s a diagrammatic vertical sectional vle'w through the cylinders and their air escape members and showing a modified plan of operation;

Flg. 3 is a diagrammatic vertical transverse sectional view through one of the cylin'ders and showing another modified plan;

Fig. is a similar view with certain parts otherwise adjusted according to a further modified plan.

In the constructional example shown in Fig.- 1 of the drawing a, b, c and d are the centres of the four working cylinders, e. is the engine case, 7 the crank shaft and g the cam shaft. The drive of the latter is eftected by the two spur wheels Ia and z. The cam shaft is in the first starting position, in whlch the auxiliary starting cams 70, Z, m and it open all the exhaust valves during a part of the compression stroke. In this p0 sitlon the engine is started by means of starting airor by hand. On combustible mixof the flywheel o and by the combustion pressures of the cylinders working with reduced compression and possibly also by the continued action of the driving means used for starting.

As soon as the cylinder (1 is in full operb is due to the position of the crank. In

the case of cylinders a and d the cranks are displaced relatively by 180. Thus, in this case, the compression resistances follow each other at equal intervals, whereby there Wlll be a better utilization of the inertia of the fly-wheel.

The'step by step displacement of the cam shaft is effected by means of the hand lever p. The handle 9 of this lever is pressed by means of a spring into the notch 7, which corresponds to the first starting osition. The notches s and t form the limits of the second and third cam shaft displacement,while the notch u fixes the lever in the operative position.

The constructional forms shown by way of example in Figs. 2-4 .difier from the arrangement of Fig. 1 substantially in this that the air escape members are jointly operated without the cam shaft taking part in this movement. As compared with an arrangement having an axially displaceable cam shaft, such an arrangement has the advantage that, on the air-escape members being operative, the auxiliary cams and the cam shaft may be omitted and that when automatically operated by the cam shaft these cams may be formed as round discs. Hence, such a constructional form of the arrangement is also adapted for engines operated by slide valves, in which the cam shaft cannot be displaced, and for reversible engines, in which a round starting auxiliary disc is correct in every position.

In the four-cylinder engine in Fig.2 the working cylinders are marked 1, 2, 3 and 4. The escape of air is effected through the cocks 5, 6, 7 and 8. The latter are in the starting position, in which all the working cylinders are decompressed, and are connected together by the rod 9. The transition to the full charge is efi'ecte by the handle 10 being moved intermittently to the left. The air escape cocks are so constructed that they are not closed simultaneously, but one after another, singly or in groups. The handle 10 must be operated cross-section with separate air escapevalves,

which may in certain cases be formed by cut-off members of the cylinders, which are provided for other purposes. The air escape members are broug t into engagement, during starting, with auxiliary cams mounted on the cam shaft, for instance, by displacing the gear between the auxiliary cams and the air escape valves. The working cylinder is marked 1, the corresponding air escape valve 5 and the cam shaft 11. The raising of the air escape valve is effected by a lever 12 and valve rod 13. The auxiliary cams for the four working cylinders mounted on t-he cam shaft are marked 14, 15, 16 and 17 The pivotal point of the lever 12 is formed by an eccentric 18, which, be-

fore the engine is put into operation, is

turned to the bottom, whereby the valve rod 13 comes in contact with the auxiliary cam 14. The air is caused to escape from the working cylinder 1 by this cam, while the cams 15 16 and 17 effect the decompression of the other working cylinders. The cams .differ from one another in the drawing by each having a different lift. The auxiliary cam 14 is lower and the cams 16 and 17 are higher than the cam 15.

When putting the en ine in operation the lever 19, which is hel in position by the notch 20 is displaced as far as the notch 21.

By this means the eccentric 18 is moved 11P-' .wards and the valve rod 13 is moved awa from the auxiliary cam 14, whereby the cy inder 1 receives the full charge and is put in operation. The remaining auxiliary cams, however, which are higher, remain in engagement with the corresponding air escape valves. By a further displacement of the lever 19 as far as the notch 22, the auxiliary cam 15 is ut out of engagement and the second wor ing cylinder thereby put in operation. Thereupon the lever 19 is moved as far as the notch 23, thus causing the cams 16 and 17 to be put out of opera tion and the third and fourth cylinders to be brought up to the normal compression pressure.

The auxiliary cams 14, 15, 16 and 17 can in case of need be formed as round discs, for instance, by being given difl'erent diameters. The air escape members will then open during all the strokes of one working cycle and will be closed by the corresponding movements of the lever 19.

Fig. 4 shows a four-cylinder engine, in

which the air is caused to escape from the case iseflected by turning the auxiliary shaft 24 with the cams 25, 26 and 27. The cam 25 opens the first, the cam 26 the second and the cam 27 the two other working cylinders. The auxiliary shaft can be displaced by hand bymeans of the handle 28, or hy-' draulic-ally by means of the cylinder 29 or by compressed air, according as the pressure ond starting position, in which the cam 25 the corresponding working cylinder.

is moved away from the air escape valve if s soon as the first combustions have started in this cylinder the lever 28 is displaced as far i as the notch 34. In this position the cam 26 is brought out of en agement with the air escape valve operate by it and the second into the operative poslt1on. the normal working position, in which, in

all the working cylinders, the compression is cut 1n.

The same method of starting and the means used therefore can, with advantage, be used for the independent step by step regulation of the output of engines, in which the change of output is not normally effected automatically, i; e. by governor arrangements, but by hand, as is for instance generally the case with the engines of motor vehicles. Such engines 'ive their greatest output when they are fe with the greatest amount of fuel, while running at the greatest speed, and their least out utin the .opposite .case. The supply of fue to the separate working cylinders should be complete and uniform, even at the lower output. When,

however, multi-cylinder engines are keptworking with a very low output, i. e. when fed at a low speed with a small amount of fuel per working stroke (for instance when "running light) ,ion the one hand it is difficult to feed the very sm ll amount of fuel in a uniformly divided s ate, on the other hand 'the efficiency willbe very low in any case and therefore a relatively large amount of fuel will be used. This well known phenomenon is accounted for, not only by the high mechanical, i. e. frictional resistances,

--in the engine, which in many respects do not vary, but also by the well known poor ther-- mal eflici'ency of any unloaded engine, as

.dividual cylinders or cyhnder compared with one which is fully loaded. The said henomena are particularly pre udicial in t e case of injection internal combustion engines with self-ignition (such as Diesel engmes, hot-bulb engines and the like) as in these engines the compression pressure must be uniformly high if an 1gn1- tion of the fuel is to take place at all, irrespective of whether the engine is r'unnm at a high or a low speed and is fully loade or running light, all the more as the thermal losses are greater at a low speed than at a relief cams on said camshaft adapted to be engaged with said valves in a.

selec-tivel sequentia manner. 7

i 3.- In starting mechanism for multiple internal combust1on engines the combination of air esca e means in thecylinders of said engines an means common to a plurality of cylinders for keeping open (1 for closing the air escape means in the cylinders in sequence in-such a manner that first only one cylinder goes into operation and later the other cylinders in suitable sequence.

4. In starting mechanism for multiple internal combustion engines the combination of 'air relief means in the cylinders of said engines and means common to all the cylinders for keeping open and for closing the air relief means in sequence in such a manner that first only one o linder goes into operation and later the ot. er cylinders in suitwhich causes the air escape means of the inoups to be closed one after the other at'di erent times a during the transition of normal working; V1en'na, Austria, July 18, 1921.

' FRIEDRICH ULLER.

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