EP2596219A2

EP2596219A2 - Method for operating an internal combustion engine and internal combustion engine

Info

Publication number: EP2596219A2
Application number: EP11733583.6A
Authority: EP
Inventors: Peter Kreuter
Original assignee: Meta Motoren und Energie Technik GmbH
Current assignee: Meta Motoren und Energie Technik GmbH
Priority date: 2010-07-23
Filing date: 2011-07-08
Publication date: 2013-05-29
Also published as: DE102010032055B4; US20130118426A1; JP2013531180A; WO2012010265A3; CN103154463B; WO2012010265A2; CN103154463A; KR20130044323A; DE102010032055A1; DE102010032055A9

Abstract

The invention relates to an internal combustion engine comprising at least one working cylinder (22) having a working chamber (36) defined by a working piston (18) and having an inlet valve (54) and an outlet valve (50), at least one compressor cylinder (20) with a compressor chamber (34) defined by a compressor piston (16) and having a fresh charge inlet valve (46), a bypass device having at least one bypass chamber (80) defined by a bypass piston (84) and connected to the compressor chamber (34) via a bypass passage (92), in which a bypass valve (106) is arranged, and wherein said bypass chamber is connected, directly or indirectly, to the working chamber (36) via an expulsion passage (96), in which the inlet valve (54) is arranged. The movement of the pistons (16, 18, 84) and the operation of the valves (46, 106, 54) are coordinated with one another in such a way that fresh charge compressed in the compressor chamber (34) is expelled into the bypass chamber (80) and is exhausted from the bypass chamber into the working chamber (36), wherein in the internal combustion engine according to the invention the bypass passage 92 leads through a cooler (100).

Description

Method for operating an internal combustion engine and internal combustion engine

The invention relates to a method for operating an internal combustion engine and an internal combustion engine operating according to such a method.

The independent patent claims are based on WO2009 / 083182. In this document, an illustrated in Fig. 1, which is taken from the cited document, illustrated internal combustion engine having a crankshaft 10 with two adjacent cranks, each connected via a connecting rod 12 and 14 with a compressor piston 16 and a piston 18 are. The compressor piston 16 is movable within a compressor cylinder 20. The working piston is movable within a working cylinder 22, wherein the working cylinder 22 is preferably lined with a cylinder tube 24.

Towards the top, the cylinders, which are preferably formed within a common cylinder housing 28, are closed by means of a cylinder head 30 which has an end wall 32 in an area overlapping the two cylinders 20 and 22, which closes off upper portions of the cylinders 20 and 22 and a trained in the cylinder head 30 overflow cylinder 33 closes down.

Between the compressor piston 16 and the cylinder head 30, a compressor chamber 34, not designated in FIG. 1, is formed whose volume in the top dead center position of the compressor piston 16 shown in FIG. 1 is at least approximately zero. Between the working piston 18 and the cylinder head 30, a working chamber 36 is formed, into which an injection valve 38 protrudes.

In the overflow cylinder 33, an overflow piston 40 is movable, which limits an overflow chamber 42.

In the cylinder head 30, a fresh air intake passage 44 is formed, in which a fresh charge intake valve 46 operates, which controls the connection between the fresh charge intake passage 44 and the compression chamber 34. The term "fresh charge" encompasses the contents "pure fresh air" and "fresh air with added fuel and / or residual gas". In the cylinder head 30, an exhaust passage 48 is further formed, in which an exhaust valve 50 operates, which controls the connection between the working chamber 36 and the exhaust passage 48.

In the end wall 32, a compression chamber 34 is connected to the overflow chamber 42 connecting overflow opening, in which an overflow valve 52 operates, which opens in a movement away from the compression chamber. A shaft of the overflow valve 52 is movably guided in the overflow piston 40 with sealing, the overflow valve 52 being movable against the force of a spring 53 into the overflow piston 40 and preferably being movable out of the overflow piston 40 with a limited stroke.

In a further opening of the end wall 32, which connects the overflow chamber 42 with the working chamber 36, operates an inlet valve 54, the shaft of which is carried out by the overflow piston 40 movable under sealing.

To operate the valves 46, 50 and 54 serve a Frischladseinlassnocken 56, an exhaust cam 58 and an intake cam 60. The transfer piston 40 is actuated by a Überströmnocken 62.

The cams are suitably formed on one or more camshafts, which are preferably driven by the crankshaft 10 at the same speed as that of the crankshaft.

The function of the internal combustion engine is explained in detail in WO2009 / 083182. The main advantage that is achieved with the described internal combustion engine compared to conventional internal combustion engines, is that the fresh charge outside the hot working cylinder 22 in the compressor cylinder 20 is compressed by the compressor piston 16 and is pushed into the overflow chamber 42, where they first further compressed by the overflow piston 40 is then pushed through the open inlet valve 54 into the working chamber 36 and burns there after or with the addition of fuel by means of the injection valve 38. Alternatively or additionally, fuel can be added to the fresh charge already upstream of the inlet valve 54 in the fresh charge inlet duct 44 or in the compressor chamber 34 or in the overflow chamber 42 so that combustible mixture is "injected" into the working chamber 36 through the open inlet valve 54. is burned and there under spark ignition or auto-ignition. The compression of the fresh charge outside the working chamber improves the efficiency of the brusque engine. The addition of fuel to the fresh charge upstream of intake valve 54 results in excellent mixture preparation, which in turn is a prerequisite for complete and substantially pollution-free combustion.

For certain fuels, when added to the fresh charge upstream of intake valve 54, there is a risk of auto-ignition already in the transfer chamber due to the high compression end temperature occurring there.

In CH 96 539 A an internal combustion engine with external multi-stage compression is described. In. a compressor cylinder is compressed by a one-piece formed with an overflow piston compressor piston fresh air in a compression chamber and pushed through a designed as a simple check valve overflow valve into a cooled buffer chamber inside a cooler, from which the cooled compacted fresh charge through another check valve through at a downward movement of the rigidly connected to the compressor piston overflow piston passes into an overflow chamber, wherein the maximum volumes of the compressor chamber and the overflow chamber are approximately equal and the size of the buffer volume is comparable to the maximum volume of the overflow chamber. From the Überströrnkammer the fresh air is pushed in an upward stroke of the overflow piston by another overflow chamber limiting check valve and a line 10 through an inlet valve of the working cylinder in the working chamber.

In DE 24 10 948 an internal combustion engine with an external two-stage reciprocating compressor and a working cylinder is described. Between the outlet valve of the first compressor stage and the inlet valve of the second compressor stage, a cooler is provided which forms a buffer volume for the fresh air compressed in the first compressor stage. The compressed in the second compressor stage fresh air is passed through an exhaust gas heat exchanger in which the compressed fresh air is heated by the exhaust gas flowing out of the working cylinder and then passes through an inlet valve into the working cylinder. The US 4,299,090 describes a reciprocating internal combustion engine with two exhaust gas turbochargers, which both supply the internal combustion engine with fresh air at high exhaust flows or high load. With only a small load and a small exhaust gas flow rate, one of the turbochargers is switched off to increase the boost pressure.

In the article by KRAMER, W .; Indirect intercooling of diesel and gasoline engines. MTZ, 02/2006, pp 104-109 an internal combustion engine is described with an exhaust gas turbocharger, in which the charge air compressed in the exhaust gas turbocharger flows through an indirect intercooler and is then supplied to the inlet of the internal combustion engine.

The invention has the object of developing the generic method and the generic internal combustion engine such that the risk of spontaneous combustion of the mixture upstream of the inlet valve 54 is reduced.

The part of the invention task that concerns the method is solved with the features of claim 1.

The dependent claims 2 and 3 are directed to advantageous Durchfuhrungsformen of the method according to the invention.

The engine of the relevant part of the invention task is solved with the features of claim 4.

Claims 5 to 10 are directed to advantageous embodiments of the internal combustion engine according to the invention.

The invention is explained below with reference to schematic drawings, for example, and with further details.

In the figures represent:

1 is a schematic sectional view of an already explained, known internal combustion engine, Fig. 2 is a view corresponding to FIG. 1 of an internal combustion engine according to the invention, Fig. 3 is a detail view of Fig. 2 and

Fig. 4 shows the internal combustion engine according to FIG. 2 relevant timing charts.

The corresponding parts are given the same reference numerals as in Fig. 1, so that only the differences from the internal combustion engine according to FIG. 1 are explained below.

A significant difference between the internal combustion engine according to FIGS. 1 and 2 lies in the fact that in the embodiment according to FIG. 2 two overflow chambers 80 and 82 are arranged in the cylinder head, in each of which an overflow piston 84 and 86 operates, which of its own Overflow cam 88 and 90 is moved. The transfer chamber 84 is connected to the compression chamber 34 via an overflow passage 92. The overflow chamber 82 is connected to the overflow chamber 80 via an overflow passage 94. From the overflow chamber 82, an exhaust passage 96, in which the intake valve 54 operates, leads into the working chamber 36.

The overflow chambers 80, 82, overflow pistons 84, 86, overflow passages 92, 94 as well as the discharge passage 96 and the valves arranged in the passages form an overflow device. The structure of the overflow passages 92 and 94 will be explained in more detail with reference to FIG.

The overflow passage 92 is formed by a through-passage 98, which passes through a wall of the cylinder head 30 and connects the compression chamber 34 with the overflow chamber 80. In the through hole 98, a cooler 100 is used, the heat exchanger channels 102 form the actual fluid passage between the compression chamber 34 and the overflow chamber 80. The overflow chamber 80 facing edge of the through hole 98 forms a valve seat 104 for the valve plate of a check valve 106 which opens against the force of a closing spring, not shown, when the pressure in the overflow chamber 80 is smaller than in the compression chamber 34th The overflow passage 94 is similar in its basic construction to the overflow passage 92 and has a passage opening 108 in a wall of the cylinder head 30 separating the overflow chambers 80 and 82. In the passage opening 108, a cooler 1 10 is used, the heat exchanger channels 1 12 form the fluid passage between the overflow chambers. The overflow chamber 82 facing edge of Durchgangsöffhung 108 forms a valve seat for the plate of a check valve 1 16, which opens against the force of a closing spring, not shown, when the pressure in the overflow chamber 82 is lower than the pressure in the overflow 80.

The check valves 106 and 16 associated, not shown closing springs are known per se in terms of their construction and their arrangement and may be, for example, the shank of the respective valve member surrounding coil springs, which are integrated into the radiator and between the radiator and a collar of the shaft support. The closing springs are designed such that the biasing force with which the respective valve member is urged against its seat, is relatively small, so that even a small, effective on the closed valve member in its opening direction pressure difference leads to a valve opening.

The design of the overflow passage 92 is advantageously such that the minimum volume of the compression chamber 34 in the TDC of the compressor piston 16 is small, advantageously less than 15%, more advantageously less than 1% of the maximum volume of the compression chamber in the BDC of the compressor piston.

The top of the valve member of the check valve 106 is in its closed state flush with an optionally surrounding edge region of the bottom of the overflow chamber 80, so that the overflow piston 84 in its UT (in Fig. 2 is the overflow piston 84 near its TDC) directly on the valve member is moved up and the remaining volume of the overflow chamber 80 in the UT of the overflow piston 84, which is given by an optional tolerance gap between the overflow piston 84 and the valve member and the volume of the heat exchanger channels 1 12, less than 15%, advantageously less than 1% of the maximum volume the overflow chamber 80 is. As can be seen from Fig. 2, the overflow piston 84 is constructed such that in his UT the or the piston rings are located immediately above the overflow passage 94 and do not run over the radiator 110.

The valve member of the check valve 1 16 is designed such that it is flush with the inner wall of the overflow chamber 82 in the closed state, so that virtually no residual volume is present here. The one or more piston rings of the overflow piston 86 are arranged such that they do not run over the check valve 1 16. The volume of the overflow chamber 82 in the TDC of the overflow piston 86 (the position of the overflow piston 86 shown in FIGS. 2 and 3) is advantageously less than 15%, more advantageously less than 1% of the maximum volume of the overflow chamber 82. This is particularly advantageous in design the exhaust passage 96 reaches.

The representation of FIG. 2 is schematic. All cams may be disposed on a common camshaft which is rotationally driven by the crankshaft 10 and rotates at the same speed as the crankshaft 10.

The function of the internal combustion engine according to FIG. 2 is explained below with reference to the control timing diagrams according to FIG. 4, the abscissa indicating the position of the crankshaft in degrees (° CA). The working piston 18 (hot piston) is located at 180 ° KW in his OT. The compressor piston 16 (cold piston) is located at 270 ° CA in its OT.

The curves indicate the following:

Curve I (dotted): stroke of the fresh air inlet valve 46

Curve II (dashed): Stroke of the overflow piston 84 (cold overflow piston); Stroke corresponds to the volume of the overflow chamber 80;

Curve III (dot-dashed): Stroke of the overflow piston 86 (hot overflow piston); Stroke corresponds to the volume of the overflow chamber 82;

Curve IV (crossed): lift of inlet valve 54 (hot spill valve): Curve V (solid): lift of the exhaust valve 50.

Assuming that the compressor piston 16 (cold piston) is at 270 ° CA in its top dead center, in which the volume of the compression chamber 34 is approximately zero and the total compressed fresh charge with closed fresh charge inlet valve 46 through the overflow 92 while cooling in the overflow 80th was pushed over. The overflow piston 84 (cold overflow piston) is located in the TDC of the compressor piston 16 approximately in its maximum position as shown in FIG. 2, in which the volume of the overflow chamber 80 is maximum.

The overflow piston 84 begins its downward movement and compresses the fresh charge located in the overflow chamber 80. At about 330 ° KW, the overflow piston 86 (Heißüberströmkolben) begins its upward movement, so that the fresh air compressed in the overflow 80 flows through the overflow passage 94 with cooling in the increasing in volume overflow chamber 82 (hot overflow) with open check valve 1 16. At about 80 ° CA, the overflow piston 84 has moved to its lowermost position, so that virtually the entire compacted fresh charge in the overflow 82, the overflow piston 86 is in its uppermost position, in which he from about 90 ° CA to about 160 ° KW remains due to corresponding contouring of the overflow cam 90. From about 160 ° CA, the overflow piston 86 moves with a steep flank in its UT, wherein at about 180 ° KW, the inlet valve 54 (hot spill valve) opens and the maximum compressed fresh charge is discharged through the Ausschubdurchlass 96 in the working chamber 36. Just before 220 ° CA, the volume of the overflow chamber 82 is minimal. Shortly thereafter, the inlet valve 54 closes, so that with downward movement of the working piston 18 (hot piston) burns the pushed out into the working chamber 36 compacted fresh charge under duty. Before the working piston 18 reaches its UT, the outlet valve 50 starts to open at about 350 ° CA and closes at about 100 ° CA, so that residual gas remaining in the working chamber 36 is further compressed by the working piston 18.

Already at 300 ° KW, the opening of the fresh charge inlet valve 46 begins, so that in the downward movement of the compressor piston 16 fresh air or fresh charge flows into the compression chamber 34 and the cycle described begins again. The exemplary described control times can be changed as long as the basic principle of the described internal combustion engine is maintained, namely pushing compacted fresh charge from the compression chamber 34 into the overflow chamber 80 with cooling when flowing through the overflow 92; Pushing over the fresh charge in the overflow chamber 80 while cooling in the overflow passage 94 into the overflow chamber 82 and expelling the fresh charge located in the overflow chamber 82 with further compression through the exhaust passage 96 with open inlet valve 54 into the working chamber 36 and the combustion chamber.

In particular, if fuel is added to the fresh charge already in the fresh charge inlet duct 44 or in the compressor chamber 34, it is advantageous if the overflow piston 86 moves downwards with a steep flank and the maximum compressed fresh charge due to the intercooling through the coolers 100 and 110 is maintained below its auto-ignition temperature, is rapidly "injected" into the working chamber 36 where it ignites with further heating. When diesel fuel is used, complete and soot-free combustion is achieved.

The described machine can also be operated with spark ignition and / or direct injection into the working chamber 36.

For the construction of the overflow passages 92 and 94 and the Ausschubdurchlasses 96 the person skilled in appropriate designs are familiar with which low residual volumes and in the overflow channels a high cooling efficiency can be achieved.

Instead of an overflow passage 92 with a radiator 100 and a check valve 106, multiple overflow passages with coolers and check valves can be used and / or the flow through a radiator can be blocked or released by means of several check valves.

Instead of one overflow passage 94, a plurality of overflow passages may be formed between the overflow chambers 80 and 82. As can be seen in FIG. 4, the movement of the overflow piston 86 is characterized in particular by the following:

The time course of the pushing or blowing of the compressed fresh charge from the overflow chamber 82 into the working chamber 36 (combustion chamber) substantially determines the course of the combustion. Therefore, the push-out function is relatively steep. The pushing out (blowing) preferably begins between about 10 ° to about 0 ° before the TDC of the working piston 18 (hot piston) and ends preferably between about 30 ° and 40 ° after TDC of the working piston 18. To achieve this remains the overflow piston 86 in his OT and its UT over relatively long periods, so that pronounced plateaus arise.

The phase shift between the compressor piston 16 and working piston 18 is preferably selected such that the highest possible compensation of the second engine order in the engine results. Preferred values are 90 ° or 270 ° lag of the working piston 18 (hot piston). At a value of 90 °, however, the time window for the overflow from the compressor side (cold side) to the working side (hot side) are very low, so that a lag of the working piston 18 of 270 ° is preferred. The excitations of the first order resulting from this arrangement can be compensated by corresponding balancing masses on the camshafts, since the described engine preferably operates with two camshafts rotating in opposite directions with crankshaft speed.

Since the upward movement of the overflow piston 84 is process-technically coupled to the movement of the compressor piston 16, and the pushing-out movement of the overflow piston 86 is coupled to the working piston 18. results from the choice of the phase shift between the movement of the working piston 18 and the movement of the compressor piston 16, the detent phase (plateau length) in the movement of the overflow piston 86th

In a simplifying modification, only an overflow chamber similar to the overflow chamber 42 of the embodiment according to FIG. 1 can be used and the overflow passage from the compression chamber 34 can be designed into the single overflow chamber as the overflow passage 92, ie with effective cooling of the overflowing fresh charge. The coolers 100 and 110 may be integrated into a cooling system, with which further areas of the internal combustion engine are cooled or can be traversed by a coolant, which is cooled in a separate circuit of ambient air.

An internal combustion engine with two flow chambers arranged in series has been described with reference to FIG. 2. It can also be arranged in series more than two overflow chambers.

The maximum volume of the overflow chamber 80 adjacent to the compression chamber 34 is, for example, between 5% and 15%, e.g. 10% of the maximum volume of the compression chamber 34. For example, each further transfer chamber following a transfer chamber has a maximum volume, for example 30% to 50%, e.g. 40% of the maximum volume of the preceding overflow chamber.

The invention has been described above using the example of an internal combustion engine with a compressor cylinder and a working cylinder. It can be provided in each case a plurality of compressor cylinder / working cylinder units, which are connected for example with a common crankshaft. It is also possible to assign a cylinder several compressor cylinders.

LIST OF REFERENCE NUMBERS

Crankshaft 56 fresh charge cams

Connecting rod 58 exhaust cam

Connecting rod 60 intake cams

Compressor piston 62 Overflow cam

Working piston 80 overflow chamber

Compressor cylinder 82 overflow chamber

Working cylinder 84 Overflow piston

Cylinder tube 86 Overflow piston

Cylinder housing 88 Overflow cam

Cylinder head 90 Overflow cam

End wall 92 overflow passage

Via flow 1 in the 94 overflow passage

Compressor chamber 96 exhaust passage

Working chamber 98 passage opening

Injector 100 radiator

Overflow piston 102 heat exchanger channels

Overflow chamber 104 valve seat

Fresh charge inlet channel 106 Check valve

Fresh charge intake passage 108 through hole

Outlet duct 1 10 radiator

Exhaust valve 1 12 heat exchanger channels e

Overflow valve 1 14 Valve seat

Spring 116 check valve

intake valve

Claims

claims

1. A method for operating a Brerinkrafuiiaschine with

a working cylinder with a working chamber bounded by a working piston with an inlet valve and an outlet valve,

a compressor cylinder having a compressor chamber bounded by a compressor piston with a fresh charge inlet valve and an overflow valve, and

an overflow chamber delimited by an overflow piston, which is connected to the compression chamber with the overflow valve open and is connected to the working chamber when the inlet valve is open, comprising the following steps:

Inflow of fresh charge into the compression chamber while increasing the volume of the compression chamber,

Compacting fresh charge in the compression chamber while reducing the volume of the compression chamber,

Pushing the compacted fresh charge into the overflow chamber,

Pushing out the compacted fresh charge in the overflow chamber into the working chamber by reducing the volume of the overflow chamber by means of the overflow piston,

Burning the fresh charge in the working chamber under increase in volume of the working chamber and conversion of thermal energy into mechanical work and

Ejecting the burned charge with volume reduction of the working chamber, characterized in that

the compressed fresh charge is cooled in the overflow from the compression chamber into the Überströrnkammer.

2. The method of claim 1, wherein

a plurality of each overflow piston limited Überströmkammern are arranged in series,

the compressed fresh charge from the compression chamber is pushed into a first of the transfer chambers,

the compressed fresh charge from a respective overflow chamber by reducing the volume of the respective overflow chamber by means of the overflow piston from the first Overflow chamber is ejected into a respective subsequent Überströmkarnmer and is cooled in the overflow from a transfer chamber into a subsequent transfer chamber, and

the compressed fresh charge from the last of the transfer chambers is pushed into the working chamber.

3. The method of claim 1 or 2, wherein the fresh charge upstream of the intake valve fuel is added, so that when the inlet valve open combustible mixture is ejected into the working chamber, which burns in the working chamber.

4. Internal combustion engine with

at least one working cylinder (22) having a working chamber (36) delimited by a working piston (18) with an inlet valve (54) and an outlet valve (50), at least one compressor cylinder (20) with a compressor chamber (34) bounded by a compressor piston (16) ) with a fresh charge inlet valve (46),

an overflow device with at least one overflow chamber (80) delimited by an overflow piston (84), which is connected to the compression chamber (34) via an overflow passage (92) in which an overflow valve (106) is arranged and which communicates with the working chamber (36) is indirectly or directly connected via a Ausschubdurchlass (96), in which the inlet valve (54) is arranged, wherein

the movement of the pistons (16, 18, 84) and the operation of the valves (46, 106, 54) are coordinated such that in the compression chamber (34) compacted fresh charge from the compressor piston (16) in the overflow chamber (80) is pushed over and is pushed out of the overflow chamber into the working chamber (36) by the overflow piston,

characterized in that the overflow passage (92) passes through a radiator (100).

5. Internal combustion engine according to claim 4, wherein the overflow device comprises a plurality of in series, each of an overflow piston (84, 86) limited overflow chambers (80, 82) each having a through a cooler (1 10) leading overflow passage (94) with each other are connected, which can be shut off by means of an overflow valve (1 16), and whose first overflow chamber (80) with the compression chamber (34) and the last overflow chamber (82) is connected to the working chamber 36.

6. Internal combustion engine according to claim 5, wherein an overflow passage by adjacent chambers connecting heat exchanger channels (102, 1 12) of a radiator (100, 1 10) is formed, which in a through hole (98, 108) is arranged, which by a to each associated chambers adjacent wall leads.

7. Internal combustion engine according to claim 5 or 6, wherein the overflow valves as check valves (106, 1 16) are formed, which open in a respective rear of the arranged in series overflow chambers.

8. Internal combustion engine according to any one of claims 4 to 7, wherein the minimum volume of the compression chamber or an overflow chamber is less than 15%, preferably less than 5% and more preferably less than 1% of the maximum volume of the respective chamber.

9. Internal combustion engine according to one of claims 4 to 8, wherein the maximum volume of the compression chamber (34) adjacent the overflow chamber (80) is smaller than that of the compression chamber and the maximum volume of a subsequent overflow chamber (82) of the arranged in series overflow chamber (80 , 82) is smaller than that of the respective previous overflow chamber (80).

10. Internal combustion engine according to one of claims 4 to 9, wherein the compressor piston (16) and the working piston (18) via connecting rods with a crankshaft (10) are connected and the or the overflow piston (84, 86) and by means of cams (88, 90) are actuated, which are driven by the crankshaft.