US2153805A - Internal combustion engine - Google Patents

Description

April 11,1939. as. KAMMER 2,153,305

INTERNAL comausnpu ENGINE Filed June 16, 19:57 '2 Sheets-Sheet 1 April 11, 1939. G. s. KAMMER 2,153,805

INTERNAL 'comsusw'rou snows 'FiledJun e .16, 19s! 2 Sheets-Sheet 2 n we 72%r Gee-rye =51 Fummar Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE Application June 16, 1937, Serial No. 148,578 In Germany June 12, 1936 3 Claims. (01. 123-33) The invention relates to internalcombustion engines. I

In reciprocating engines in which the ignition of the fuel is efiected by bringing the temperature 5 in the working cylinder to the ignition temperature of the fuel by compression, it is necessary for achieving as complete combustion as possible to take precautions for a very intimate mixture of fuel and charging air. This mixture is usually carried-out by producing a current of air during the fuel admission.

Instead of the usual method of carrying out the compression in the working cylinder up to the occurrence of the ignition temperature of the fuel, it has already been proposed to produce this current of air by the use of a space standing in communication with the operating cylinder by comparatively small ports or passages. This space was increased after the attainment of a lower compression pressure by shifting a controlled auxiliary piston, so that in comparison with the pressure ruling in the working cylinder a lower pressure was formed in this space and the air flowed from the working cylinder through the connecting ports into it. The fuel was then sprayed into the current of air thus produced and mixture took place without combustion. The final compression pressure, i. e. the pressure at which the temperature of the air reaches the ignition temperature of the fuel, was then provided by the auxiliary piston as soon as the latter on its return stroke reduced the space in question, the fuel-air mixture being then displaced from this space into the working cylinder.

In this method of operation all the elements of the driving gear for the auxiliary piston had to be dimensioned to withstand the force due to the full compression pressure, so that this driving gear came out unduly large and heavy. on one hand this denoted a considerable increase of weight and on the other hand the necessary rapid movement of the elements was made much more dimcult by the large inertia forces. In the engine according to the invention the 5 auxiliary piston has nothing to do with the compression, and thus its driving gear does not require to be designed for the force due to the final compression pressure, so that the various elements of this gear can be made much lighter and the friction losses are also less. According to the invention the working pisto efiects compression up' to the attainment of the ignition temperatureof the fuel, as is the case in the commonly known-engines. Onspraying in F the fuel there is a lower pressure in the space standing in communication with the working cylinder, which was increased by the shifting of the auxiliary piston, and the inflow taking place from'the working cylinder efiects the mixture of I fuel and air. Since, however, the air has already 5 reached the ignition temperature of the fuel, ignition now takes place, and combustion is eifected almost exclusively in the auxiliary piston space. The pressure increases in thisspace in consequence of the combustion and becomes higher 10 than the pressure ruling in the working cylinder, so that, with the further assistance of the fall of pressure due to expansion during the working stroke, the combustion products are blown out from here into the working cylinder. Towards the end of the expansion process, or duringexslide or the like closing and opening the charging air admission or the exhaust port.

The accompanying drawings show diagrammatically'by way of example a-constructional 30 form of a two-cycle engine according to the invention.

Figures 1 and 2 show the engine in section through the axis of the working cylinder, Fig. l at the upper dead centre of the working piston 35 and Fig. 2 at the lower one. Figs. 3 and 4 show the driving mechanism for the auxiliary piston, in side elevation and in front view respectively.

I The working piston 2 moving upwards in the working cylinder I compresses the air previously 4 introduced into the cylinder space until the flnal compression pressure is reached. While the piston is traversing the last 30 or 20 degrees before the upper dead centre (measured on the crank shaft) the auxiliary piston 3 has already been 5 pushed by a spring l3 into its lower position as shown in Figure 1, so that in the space 4- above the auxiliary piston 3 there is a lower pressure than in the cylinder I, and the air compressed by the piston 2 flows at high speed into the space I 50 through the connecting port 5 until the upper dead centre is reached. In the meantime the necessary quantity of fuel is sprayed into the current of air by means of the jet 6 in a direction parallel to the current as shown. The fuel 55 2 a,1ss,sos

prayed in ignites and burns, combustion taking place almost exclusively in the space 4. When the piston 2 has reached the upper dead centre the whole mixture is so to speak located in the 6 space 4. In consequence of the combustion of the fuel the pressure rises, equalizes itself in the spaces standing in communication with each other and pushes the piston 2 to its lower dead centre doing work. As soon as the piston 2 partly 10 uncovers the exhaust port I, the auxiliary piston l is pushed up to the position of Figure 2 by the cam il driven from the crank shaft II by means of the toothed wheels l8 and i1, and acting on the 8. The volume of the space l is thus 16 reduced nearly to zero and the combustion products located therein are pushed out into the cylinder 1 having only an inconsiderable pressure to overcome. At the same time the piston valve 8 mounted on the rod 8 uncovers the admission port ill, so that the scavenging and charging air flow through port ii and space I! into the cylinder space and drive out through the port I the combustion products located here, together with those displaced from the space 4. Hereupon the 2 piston 2 commences its upward travel, closes the exhaust port, then the admission port. and compresses thefresh charging air present in the cylinder until it reaches the final compression pressure. Towards the end of the compression 30 strokerthe process described at the commencement begins afresh.

The fuel supply can also take place'in any desired way differing from that shown, e. g. the jet I can also be arranged above the working piston 2 and the particles of fuel be led in the direction of the connecting port I, 'or the fuel can be sprayed into the space 4 in cpuntercurrent to the air current flowing into it. In some circumstances it is suilicient to place the fuel in a suit- & able hollow in the space I.

, In the constructional rot-m shown in the drawlogs the admission port II on theside of the working piston is larger in the stroke direction than the exhaust port I, so thatit is only at a later I point of time than the exhaust port that it is completely closed by the rising piston; the same eifect can be just as well achieved by arranging the admission port higher than the exhaust port, or arranging several admission ports one above an- 60 other.

The accurate time adjustment of the movement of the working piston 2 and of the auxiliary piston 8 in relation to each other is best effected in actual practice, namely in such a way that the 66 fuel consumption is the lowest possible.

The movement of the auxiliary piston I can be displaced'in time even during operation by means of a suitable arrangement, a. g. by employi a a steeply pitched nut l8 rigidly connected to the 00 toothed wheel II which in this case is movable on the shaft ll of the cam ll. Since the pin ll fastened to the shaft ll lies on twosides against the steepscrewsurface of the nut II, the shaft' "will take partintherotationofthe toothed 66 wheel II. By shifting the bifurcated lever 22 pivotably mounted on the stationary pin II, the toothed wheel II and the nut ll can be axially displacedontheshaft ll.wherebythepinllis caused to slide over the screw surfaces of the nut 70 ,andtheshaft iltoslightlyturninrespectto the toothed wheel-l1. Byasimilararrangement for instance when starting the engine the occurrmceofthelowerpressurecanbe'displaced-toa yhtcr point of time than when running normally, 76 andthmahighcrcompressicncanbeachieved.

To control the admission and exhaust, valvesor other-elements can be provided, and the chargingaircanbecompressedinthe crank caseorby' means of a separate blower.

What I claim is:

1. A compression ignition engine comprising a working cylinder and working piston, an auxiliary cylinder, a piston valve therein for the admission of combustion and scavenging air, an auxiliary piston to vary the volume of the end of the aux- 0 iliary cylinder, a restricted communication between the end of the auxiliary cylinder and the working cylinder, common means for respectively operating the piston valve and the auxiliary piston to uncover the admission port and reduce the volume of the end of the auxiliary cylinder when the working piston is near the end of its expansion stroke, and to cover the admission port and increase the volume of the end of the auxiliary cylinder when the working piston is in position on its compression stroke producing compression pressures in the working cylinder which result in ignition temperatures, and a fuel injection 'noszle located in the restricted communication between working cylinder and auxiliary cylinder and producing a fuel jet directed into the latter.

2. A compression ignition engine comprising a working cylinder and working piston, an auxiliary cylinder containing a piston valve for the admission of combustion and scavenging air, an auxiliary piston'to vary the volume of the end oi. the auxiliary cylinder, a restricted communication between the end of the auxiliary cylinder and the working cylinder, a fuel injection nozzle 85 located in the restricted communication and producing a fuel jet directed into the auxiliary cylinder, cam gear to open the admission piston valve and move the auxiliary piston to reduce the volume of the end of the auxiliary cylinder towards 40 the end of the expansion stroke of the working plstomandaspringtoclose saidpistonvalve andmovetheauxiliarypistontoincreasethe 'volume of the end of the auxiliary cylinder when providedinthecyiinderwall'anduncoveredby theworkingmstonneartbeendofiuoutward stroke,andanadmi ssionportoppositetheexhaustportbmextemiingfurtherthantheexhaustportintheinwardstrokcdirecflon.

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