US2145415A - Internal combustion engine - Google Patents

Description

JML 31, i939 l A. ECKE-MLLER M INTERNAL COMBUSTION ENGINE Filed April 2, `1936 2 sheets-Sheet 1 Jan. 4.31, 1939. A. Bom-:MULLER INTERNAL QOMBUSTION ENGINE www Filed April 2, 1936 Sheets-Shei 2 #gill Jn @fen tor maaier lan. 31, 193e @MEAN UNITED STATES @PATENT @FWCE INTERNAL COIWBUSTION ENGINE Alfred Bokemiiller, Gaggenau, Baden, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Application April 2, 1936, Serial No. 72,255 Y In Germany April 4, 1935 20 Claims. (Cl. 12B- 65) My invention relates to internal combustion interval between the opening of the outlet and engines of the two-cycle type and has for its obthe dead center instant in such machines equals ject to improve the scavenging operation and to the interval between the dead center instant and obtain an increased eiiciency. the closing of the outlet, any reduction of the 5 More particularly, my invention relates to tWofirst interval will equally reduce the second intercycle engines in which the inlet and the outlet val and will thus adversely affect the emciency oi ports are provided in the cylinder walls and are the scavenging operation. On the other hand, controlled by the piston and by a tubular sleeve any increase of these intervals reduces the eiecsurrounding the same. tive stroke and involves a loss of fresh charge.

1o I attain the objects of my invention by con- A higher effective pressure has been attained l0 trolling the relative motion of the piston and with two-cycle engines in which one or more the control sleeve in such a manner that the valves are used to control the scavenging operatimed relationship of the instants at which the tion, the scavenging air rinsing the 'cylinder from inlet and outlet ports are opened and closed by one end thereof to the other.

lo the piston and the sleeve is non-symmetrical rel- By the non-symmetrical controlas above eX- liti ative to the instant of the passage of the piston plained I secure an ellcent scavenging operation through its lower dead center point, the interval and a high average effective pressure by simple between the opening of the outlet and the dead means, a single control sleeve only being procenter instant being larger than the interval vided and the inlet and outlet ports being lo- 2o between the dead center instant and the closing cated in the cylinder walls close to the lower dead 20 of the outlet and/or the interval between the center point which is of particular advantage for opening of the inlet and the dead center instant the control of the inlet and outlet ports in high being shorter than that between the dead center speed engines. instant and the closing of the inlet. Preferably, The provision of a plurality of groups of inlet Q5 the control of the inlet and outlet ports is so ports has the further advantage that the control 25 timed that the outlet is opened before the inlet is thereof may be differently timed in a simple manopened and that the outlet is closed shortly bener and that a plurality of scavenging currents iore cr substantially together with the inlet. of different directions or different pressures may A highly enicient scavenging operation will be be produced in a suitable succession, whereby attained by the provision of two groups of inseparate currents of air or gas may be used for 30 let ports which are controlled in a differently scavenging the cylinder and for charging it.

timed manner, one group of inlet ports being Further objects of my invention will appear controlled by the piston only, whereby the timed from the description following hereinafter and relationship of the instants of opening and closthe features of novelty will loe-pointed out in 3 3 ing is symmetrical relative to the instant of the the claims. 35 lower dead center position of the piston, and the A preferred embodiment of my invention is other group of inlet ports being controlled by the illustrated in the drawings. combined function of the piston and the control Fig. 1 shows a partial axial section through a sleeve so as to be left open after the iirst group cylinder of the machine illustrating a part of L1 n has been closed. the crank shaft and the means for operating the 40 My invention is equally applicable to machines piston and the control sleeve, the section being of the Diesel type in which a liquid fuel is intaken along line l-I of Fig. 2;

jected into the cylinder which is charged with Fig. 2 is a section taken along line 2-2 of air or to engines of the type in which a gaseous Fig. l and .17, or vaporized fuel is compressed in the cylinder. Figs. 3 to 8 are diagrams illustrating the rela- 45 Experience has shown that the average effective positions of the cylinder, the control sleeve tive pressure attainable in two-cycle engines is and the piston in successive instants. limited, when the inlet and outlet ports provided Fig. 9 shows a partial axial section through in the cylinder walls are solely controlled by the the cylinder illustrating a second form of the 5o piston with a timed relationship of the instants inlet port. 50 of the opening and closing which is symmetrical Fig. 10 shows a partial axial section through with regard to the lower dead center instant. the cylinder illustrating the main inlet port ol This applies particularly to automotive engines the engine. y which are designed to produce as high a torque In Fig. 1, the cylinder g provided with the 55 as possible over a large range of speeds. As the customary cooling jacket ill supports on its gg upper end a cylinder head or cover Il which has a cylindrical downward projection I2. This projection is slightly spaced from the inner wall oi' the cylinder g so as to define an annular gap I3 therewith. A fuel-injecting mechanism I4 which may or may not include a pre-combustion chamber is inserted in the cylinder II in central position to inject liquid fuel into the highly heated air compressed in the cylinder. The air is fed into the cylinder from a source of compressed air, such as a scavenging pump (not shown) through two groups of inlet ports e and e', when the piston k approaches its lower dead center position.

Substantially at the same time the outlet ports a are opened. It will be noted from Fig. 2 that the inlet ports e and e traverse the cooling jacket I0 and the cylinder y and have the general directions indicated by the arrows in Fig. 2. These arrows converge towards a point m which is eccentrically located in the cylinder remote from the outlet ports a. Preferably the inlet ports e and e' are substantially radially directed to the axis of the cylinder, as sliown in Fig. 1, or these ports may be slightly upwardly directed at an acute angle with the axis of the cylinder g, as shown in Figs. 9 and 10. Moreover, it will be noted that the main inlet ports e are located at a slightly lower level than the auxiliary inlet ports e' and that the outlet ports a are substantially radially directed and diametrically opposed to the ports e. Some of the ports are controlled by the combined function of the piston k and of a sleeve valve or slide s which is guided within the cylinder. The upper end of the slide projects into the annular gap I3 and its lower end is provided with two diametrically opposed trunnions I5. Intermediate its ends the slide s is provided with two groups of openings es and as, the openings e's cooperating with the inlet ports e .and the openings as with the outlet ports a. Moreover, the slide is provided with two longitudinal slots 1' extending from its lower end upwardly approximately to the level of the upper walls of the openings e's. It will be obvious, however, that the slots r need not extend all the way to the bottom of the sleeve s but may be cut off near the bottom to form rectangular openings. These slots r straddle the mouths h of the ports e which project inwardly from the cylinder y for direct cooperation with the piston k. As will be seen from Fig. 10, the mouths h are of such a form that piston k in its lower dead center position will stillbe in contact therewith.

If desired, these projecting mouths h may be made separate from the cylinder g and suitably inserted therein for easy manufacture although they are shown integral with the cylinder in the drawings. The section of the crank shaft which is allotted to the cylinder shown in Fig. 1 is provided with three crank pins. The central crank pin 20 is connected with the piston k by the customary connecting rod 2| while the two other crank pins are connected with the trunnions I5 by auxiliary connecting rods 22. Preferably, the crank pin 20 is displaced from 130 to 180 degrees in advance of the two lateral crank pins to secure the proper timing of the control slide s relative to the piston k.

The slots r must be so dimensioned with reference to the stroke imparted to the reciprocatory sleeve s by the cranks and the connecting rods 22 that the mouths h will not interfere with the upper walls of the slots r. If desired, rectangular openings may be substituted for the slots r, as

previously described. The piston k is guided by the sleeve s.

The openings as and es cooperate with the upper end of the piston in controlling the outlet ports a and the auxiliary inlet ports e', the control sleeve s moving substantially in a direction opposite to that of the piston. The opposite motion of the piston and the control slide or sleeve has the advantage that the ports are fully opened and fully closed at a higher speed.

The main inlet ports e, however, are controlled solely by the piston independently of the motion of the control slide or sleeve s.

The operation will be explained hereinafter with reference to the diagrams shown in Figs. 3 to 8 which illustrate successive instants during one revolution of the crank shaft. In Fig. 3 the elements assume the position in which the opening of the outlet ports a commences. The crank pin 20 operating the piston is in the position A1 and the crank pins operating the control sleeve in the position B1.

It will be noted that the point A1 is ahead of the point B1 by the angle B. This angle may be chosen from to 180 degrees. 'I'he piston moves downwardly and the control sleeve upwardly. Therefore, the outlet ports a will be very quickly uncovered by the upper edge of the piston and by the opening as of the control sleeve. The main inlet ports e are still covered by the piston and the auxiliary inlet ports e' by the control sleeve.

Fig. 4 illustrates the instant at which the main inlet ports e are uncovered by the upper edge of the piston, the main crank having arrived at E1.

Fig. 5 shows the instant at which the opening of the auxiliary inlet ports e' by the sleeve opening es commences, the main crank arriving at E1 shortly after having passed the lower dead center position UT. At this time, the sleeve s is-rapidly moving downwardly, whereby the auxiliary inlet ports e' will be uncovered within a short interval while the outlet ports a are being closed. The main inlet e is fully opened.

The closing of the outlet ports is effected by the opposite motion of the downwardly moving sleeve and of the upwardly moving piston. The end of the closing operation is illustrated in Fig. 6. In this instant, the crank has arrived at the point A2. The main inlet ports e are partly covered again by the piston, whereas the auxiliary inlet ports are being uncovered by the opening e's.

Shortly afterwards, the elements arrive at the position shown in Fig. 'l in which the crank passes through the point Ez. At this instant, the main inlet ports e have just been completely covered by the piston k, Whereas the auxiliary inlet ports e' are just fully opened.

In Fig. 8 the crank arrives at the point Ez. At this instant, the auxiliary inlet ports e' are fully closed. As the upward motion of the piston and the downward motion of the sleeve are comparatively rapid, the auxiliary inlet ports e were closed at a high speed. 'I'his has the advantage, that the full cross-section of the auxiliary inlet ports e' is kept open until shortly before the closing begins, namely until the instant of Fig. 7, whereby a very effective scavenging or charging or supercharging operation is rendered possible without delaying the closing of the auxiliary inlet to such an extent that the scavenging or charging medium entering therethrough would meet with a considerable counteracting compression pressure.

In Fig. 6 the entire control diagram is shown with reference to the crank circle. It will be noted that the interval between the instants Ai and UT is larger than the interval between the instants UT and A2 which means that the outlct ports are opened sooner with reference to the lower dead center point than they are closed. Inversely, the interval between E1 and UT is shorter than the interval between UT and the instant E'z at which all of the inlet ports are completely closed. Therefore, the outlet diagram A1-A2=a and the inlet diagram Ei--Ei overlap in a favorable manner, as is shown in Fig. 6.

The inlet diagram is obtained by the control diagram El-Ezze of the main inlet ports situated symmetrically relative to the lower dead center point of the piston and by the control diagram E'1-E'2=e' of the auxiliary inlet ports situated very non-symmetrically relative to the dead center point.

The main inlet ports may serve to scavenge the cylinder, whereas the auxiliary or additional inlet ports are used in the main for charging and supercharging the cylinder. The charging medium may be any suitable fluid such, for example, as air, when the invention is applied to Diesel engines, or a gas or a fuel mixture when the invention is applied to machines provided with a carburetor. In the two latter cases the gas or fuel mixture may be fed to the cylinder through the auxiliary inlet ports, whereas pure scavenging air is fed to the main inlet ports. Moreover, the pressure at which the air charge enters through the main or auxiliary inlet ports may be made different by suitably choosing and dimensioning the sources supplying the scavenging medium.

In the embodiment illustrated in the drawings, provision is made for a supercharging of the cylinder through the auxiliary inlet ports. However, the control points A1, A2, E1, Ez, E'1, Ez may be so arranged relative to each other that Ez coincides with A2 or that A2 is preceded by E2 and E'2 without departing from the above described principal relation of the inlet or outlet intervals.

In view of the low position of the control openings, the sleeve may be so designed that it terminates substantially in the level of the openings as and e's and does not engage the gap I3.

Further modifications will readily appear to anyone skilled in the art.

What I claim is:

1. In a two-cycle internal combustion engine, comprising in combination, a cylinder, a slide valve in said cylinder, a piston in said slide valve, an inlet and outlet port for said cylinder controlled by said piston and slide valve, a further inlet port for said cylinder controlled by said piston alone, and means drivably connecting said piston with said slide valve, the angular relationship of said connecting means being such that the inlet and outlet port controlled by the piston and slide valve will be controlled asymmetrically and the inlet port controlled by the piston alone will be controlled symmetrically with respect to the lower dead center point of the piston.

2. The combination according to claim 1 including means for introducing a stream of charging fluid into saidcylinder through said rst inlet port and means for introducing a stream of scavenging uid into said cylinder through said second inlet port.

3. In a two-cycle internal combustion engine, the combination comprising a cylinder provided with two groups of inlet ports and one group of outlet ports, a tubular sleeve having cooperating openings guided for reciprocatory movement in said cylinder, a piston guided for reciprocatory movement in said sleeve and cooperating with the openings in said sleeve for controlling one group of said inlet ports symmetrically with respect to the lower dead center point of said piston, and means interconnecting said piston and sleeve for controlling the other group of inlet ports asymmetrically with respect to said lower dead center point, and in such a manner that said second group of inlet ports remain open after said first group of said inlet ports has been closed, and means for supplying said rst group of inlet ports with a scavenging fluid, and means for supplying said second group of inlet ports with a charging uid.

4. The combination according to claim 3 in which the ports oi" each group are circumferentially distributed and in which the second group of inlet ports are adjacent the outlet ports.

5. The combination according to claim 3 in which the ports in each group are circumferentially distributed, andl in which the second group of inlet ports' are adjacent the outlet ports, al1 of said inlet ports converging toward a point eccentricaly located within the cylinder at the side remote from said outlet ports.

6. In a two-cycle internal combustion engine, the combination comprising a cylinder provided with inlet and outlet ports, a tubular sleeve having cooperating openings and guided for recip rocatory movement in said cylinder, a piston guided for reciprocatory movement in said sleeve, a crank shaft having a plurality of crank pins and a plurality of connecting rods one of which joins one of said crank pins to said piston and the other o-f which joins the other crank pins to said sleeve, said piston operating crank pin leading said sleeve operating crank pins by approximately 130 to 180, whereby said `inlet and outlet ports are controlled asymmetrically with respect to the lower dead center point of said piston, the outlet ports being opened sooner with respect .to said deadcenter point than they are closed and the inlet ports being opened later with respect to said dead center point than they are closed.

7. In a two-cycle internal combustion engine. the combination comprising a cylinder provided with two groups of inlet ports and with outlet ports, a tubular sleeve having cooperating openings for controlling one group of inlet ports and said outlet ports and guided for reciprocatory movement in said cylinder, a piston guided for reciprocatory movement in said sleeve and controlling a second group of said inlet ports and means interconnecting said sleeve and piston in such a manner that the first group of inlet ports and outlet ports are controlled in an asymmetrically timed relationship relative to the passage of the piston through its lower dead center point.

8. In an internal combustion engine, the combination of a cylinder having two groups of inlet ports and one group of outletk ports, the inlet ports of one of said groups having internally projecting mouths, a tubular sleeve having elongated openings circumferentially closely fitting said projecting mouths, guided for reciprocatory motion in said cylinder and adapted to control dii said second group of inlet ports, and a. piston guided for reciprocatory motion in said sleeve and adapted to open and close said mouths.

9. A two-cycle internal combustion engine comprising in combination, a cylinder, a slide valve in said cylinder, a piston in said slide valve, an inlet and outlet port for said cylinder controlled by said piston and slide valve, and a further inlet port for said cylinder controlled by said piston alone.

10. A two-cycle internal combustion engine comprising in combination, a cylinder, a slide valve in said cylinder, a piston in said slide valve, an inlet and outlet port for said cylinder controlled by said piston and slide valve, a further inlet port for said cylinder controlled by said piston alone, and means drivably connecting said piston and side valve for opening the rst named inlet port shortly after the outlet port has been opened and closing it shortly after the outlet port has been closed, and for opening the second inlet port shortly before the outlet port has been closed and closing it after the outlet port and the first named inlet port have been closed.

11. The combination according to claim 9 in which the inlet ports controlled by the piston and slide valve are arranged opposite to the outlet ports and are adapted to charge the cylinder, and the second named inlet ports controlled by the piston alone are adjacent to said outlet ports and are adapted to scavenge the cylinder.

12. The combination according to claim 9 in which the inlet ports controlled by the piston and slide valve are arranged opposite to the outlet port and are adapted to charge the cylinder and the second named inlet ports controlled by the piston alone are arranged adjacent to said outlet port and are adapted to scavenge the cylinder, the outlet port being substantially radially directed to the. axis of the cylinder and the inlet ports being slightly upwardly directed and converge toward a point eccentrically located within the cylinder at the side remote from said outlet ports.

13. A two-cycle internal combustion engine comprising in combination, a cylinder, an outlet port for said cylinder directed radially to the axis of said cylinder, an inlet port for said cylinder slightly upwardly directed at an angle to the axis of the cylinder and arrangedk opposite to the outlet port, a further inlet port slightly upwardly directed to the axis of the cylinder and located adjacent the outlet port at a slightly lower level than said rst inlet port, both of said inlet ports converging towards a point eccentrically located within the cylinder at the side remote from said outlet port, a mouth on said further inlet port projecting inwardly from said cylinder, a tubular slide valve in said cylinder having opposite ports respectively controlling the opposite inlet and outlet ports and having a longitudinal slot straddling the mouth of said further inlet port, a v

piston in said tubular slide valve controlling the ports in said slide valve and the further inlet port in said cylinder and means drivably connecting the piston with the slide valve, the angular relationship of such connecting means being such that the inlet and outlet ports controlled by the piston and slide valve will be controlled asymmetrically and the inlet port controlled by the piston alone will be controlled symmetrically with respect to the lower dead center point of the pis- 14. A two-cycle internal combustion engine comprising in combination, a cylinder, an outlet port for said cylinder directed radially to the axis of the cylinder, an inlet port for said cylinder slightly upwardly directed at an angle to the, axis of the cylinder and arranged opposite said outlet port, a further inlet port slightly upwardly directed to the axis of the cylinder and located adjacent said outlet port at a slightly lower level than said first inlet port, both of said inlet ports converging toward a point eccentrically located within said cylinder at the side remote from said outlet port, a mouth on said further inlet port projecting inwardly from said cylinder, a tubular slide valve in said cylinder having opposite ports respectively controlling the opposite inlet and outlet ports and having a longitudinal slot straddling the mouth of said further inlet port, a piston in said tubular slide valve controlling the ports in said slide valve and the further inlet port in said cylinder, means drivably connecting the piston with said slide valve, the angular relationship of this connecting means being such that the inlet port controlled by said slide valve will be opened shortly after the outlet port has been opened and will be closed shortly after the outlet port has been closed, and the inlet port controlled by the piston alone will be open shortly before the outlet port has been closed and will be closed shortly after the outlet port and said first main inlet port have been closed, whereby the inlet and outlet ports controlled by said piston and slide valve will be controlled asymmetrically and the inlet port controlled by the piston alone will be controlled symmetrically with respect to the lower dead center point of the piston. 15. A two-cycle internal combustion engine as set forth in claim 13 in combination with means for introducing a stream of charging iiuid into said cylinder through said first inlet port, and means for introducing scavenging fluid into said cylinder through said further inlet port.

16. The method of controlling a two-cycle internal combustion engine having two groups of inlet ports and one. group of outlet ports, including the steps of opening the outlet ports, opening one group of inlet ports a short time thereafter, closing the outlet ports, closing said first group of inlet ports a short time after said outlet ports have been closed, opening the second group of inlet ports a short time before the outlet ports have been closed and closing said second group of inlet ports shortly before said outlet ports and said rst group of inlet ports have been closed.

17. The method of controlling a two-cycle internal combustion engine having two groups of inlet ports and one group of outlet ports, including the steps of controlling one group of inlet ports and said outlet ports asymmetrically with respect to the lower dead center point of the cylinder piston, and controlling the other group of inlet ports symmetrically withl respect to the lower dead center point of the cylinder piston.

18. The method according to claim 17 including the steps of introducing a stream of chargf with inlet and outlet ports, a tubular sleeveg having cooperating openings and guided for reciprocatory movement in said cylinder, a piston guided for reciprocatory movement in said sleeve, and means interconnecting said sleeve and piston in such a manner that said inlet and outlet ports are asymmetrically controlled, the outlet ports being opened before the inlet ports with respect to the lower dead center point of the piston and both said inlet and outlet ports being closed at substantially the same time.

20. In a two-cycle internal combustion engine, the combination comprising a cylinder provided with groups of inlet and outlet ports, said outlet ports being radially directed in one side of said cylinder and said groups of inlet ports being axially displaced on the opposite side of said cylinder and directed at an oblique angie to the radius and axis of said cylinder, a tubular sleeve having cooperating openings and guided for reciprocatory movement in said cylinder, a piston guided for reciprocatory movement in said sleeve, and means interconnecting said sleeve and piston in such a manner that said inlet and outlet ports are asymmetrically controlled, the outlet ports being opened sooner with respect to the lower ldead center point of the piston than they are closed, and said inlet ports being opened later with respect to said dead center point than they 10

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