WO2004022945A1

WO2004022945A1 - Reciprocating piston engine and piston therefor

Info

Publication number: WO2004022945A1
Application number: PCT/EP2003/008892
Authority: WO
Inventors: Peter Pelz; Wilfried Ball
Original assignee: Peter Pelz; Wilfried Ball
Priority date: 2002-08-12
Filing date: 2003-08-11
Publication date: 2004-03-18
Also published as: AU2003255414A1

Abstract

A reciprocating piston engine contains at least one cylinder (2), inside of which a piston works while forming a working chamber (6). Said piston comprises a skirt that, while sealing, is guided in a linearly displaceable manner through a partition wall of the cylinder formed by on the side of the piston facing away from the working chamber, and joins the piston to a crank mechanism containing a crankshaft. The space between the piston and the partition wall forms a reloading chamber that is connected to the surroundings via an intake valve device (60). In the area of the bottom dead center of the piston, an overflow device (56) opens an overflow path leading from the reloading chamber into the working chamber. An exhaust valve device (64, 66, 68) connects the working chamber (6) to an exhaust duct (70) when the piston is located in the area of the bottom dead center. The invention provides a low-vibrating, fuel-efficient, high-torque, powerful and light two-stroke engine.

Description

Reciprocating internal combustion engine and pistons therefor

The invention relates to a reciprocating piston internal combustion engine according to the preamble of claim 1. The invention further relates to a piston, in particular for such a reciprocating piston internal combustion engine.

A generic reciprocating internal combustion engine is known from DE 100 04 103 AI. In this known reciprocating piston internal combustion engine, which works, for example, according to the two-stroke principle, a conventional outlet valve designed as a poppet valve is provided in the head of the cylinder.

The invention has for its object to simplify a generic reciprocating internal combustion engine while maintaining or improving its efficiency in its structure.

This object is achieved with a reciprocating piston rafting machine according to claim 1.

The dependent claims 1 to 10 are directed to advantageous embodiments and developments of the reciprocating piston internal combustion engine according to the invention.

Characterized in that the Hubkolbenbrennlα aftmaschine ^invention, not disposed in their head, having driven exhaust valve of the crankshaft forth, it may be constructed such that it requires no camshaft. The structure and the energy consumption for actuating the exhaust valve device are thus simplified.

The claim 11 characterizes a piston as it can be used advantageously for a reciprocating piston internal combustion engine according to the invention. The invention is explained below with reference to schematic drawings, for example and with further details.

They represent:

1 shows a schematic central section through an embodiment of a reciprocating piston internal combustion engine according to the invention,

2 shows a partial section in the plane II-II of FIG. 1,

3 shows a partial section in the plane 11-11 in FIG. 1 with a modified embodiment of a crank mechanism,

4 shows a section in the plane πi-IH of FIG. 1,

5 shows a schematic view of a valve disk,

6 shows a schematic end view of a reciprocating piston internal combustion engine,

7 is a view like FIG. 4 of a modified embodiment of an internal combustion engine,

Fig. 8 is a longitudinal section through a piston, and

Fig. 9 shows a cross section through a piston skirt.

According to FIG. 1, a piston 4 works in a cylinder 2 of a reciprocating piston internal combustion engine which is closed at the top by means of an end wall 1, forming a working chamber 6 between the piston 4 and the upper region of the cylinder 2. The piston 4 has a shaft 14 which, for example, is rigid is connected to the piston 4, which shaft extends between two crankshafts 16 and 18 and ends in a supporting part 20, which is advantageously guided in a cylinder extension 22 of an engine housing, generally designated 24, the axis of the cylinder extension 22 being that of the cylinder 2 coincides. The supporting part is connected to each of the crankshafts 16 and 18 via connecting rods 26 and 28 arranged symmetrically to one another outside the cylinder axis.

Fig. 2, which shows a partial view of the sectional plane II-II of Fig. 1, shows parts of the crank mechanism. Each crankshaft 16 and 18 consists of a pair of disks with two disks 30, 32 and 34, 36, each having one in Motor housing shaft 38, 40 are non-rotatably connected. The pairs of disks are mutually rotationally engaged via external teeth 42, 44 formed on at least one of the disks, so that they rotate at the same speed but in opposite directions.

The arrangement is overall symmetrical to the cylinder axis in which the shaft 14 extends between the disks. Each disk has a connecting rod pin 46 on which the connecting rods 26 and 28, not shown in FIG. 2, are mounted. Thus, the support member 20 and thus the piston 4 is connected to the crank mechanism via four connecting rods.

FIG. 3 shows an embodiment of a crank mechanism that is modified compared to FIG. 2. The two disks 30, 32 and 34, 36 of a pair of disks are each rotatably connected to one another via an eccentrically arranged crank pin 46 or 46 ₂ and are attached to the motor housing by means of shaft stubs 38 _l5 38 ₂ or 40 _l5 40 ₂ arranged concentrically on them stored. In the crank mechanism according to FIG. 3, each crankshaft 16 or 18 is connected to the supporting part 20 only via a connecting rod which is mounted on the connecting rod journal 46j or 46 ₂ .

The connecting rods 26 and 28 in the described construction, in which they are connected to the piston 4 or its shaft 14 on the side of the crankshafts 16 and 18 facing away from the piston, are only subjected to tension with the exception of the overrun mode of the engine, so that since no high pressure or kink resistance is required, they can be designed as simple tension struts in the form of flat stamped parts, for example.

The support member 20 is advantageously not designed as a complete disc that fills the entire cross section of the cylinder extension 22, but in such a way that when the support member 20 moves up and down, the air in the crankcase can flow around the support member 20 without loss of flow.

The cylinder 2 is closed off from the crank mechanism by a partition 48, through which the shaft 14 extends in a sealingly guided manner. In this way, a fresh charge chamber 50 is formed between the piston 4 and the partition 48, the volume of which is minimal when the piston 4 is at its bottom dead center. In the area of the bottom dead center of the piston 4 (shown in FIG. 1), an annular space 52 is formed on the outside of the cylinder and extends around part of the circumference of the cylinder. The annular space 52 is connected to the fresh charge chamber 50 and the working chamber 6 below the piston via radial passage openings 54 and above the piston via radial passage openings 56.

Fig. 4 shows a section in the plane 111-111 of FIG. 1, which extends through the upper passage openings 56. According to FIG. 3, the annular space 52 encompasses a circumferential area of advantageously more than 180 ° of the cylinder 2 and starts from an intake duct 58 in which an inlet valve 60 works. The inlet valve 60 can be designed, for example, as a non-return valve which opens when the vacuum in the annular space 52; it can also be an electrically or otherwise actuated valve. A throttle valve 62 is arranged upstream of the inlet valve 60, in particular if the inlet valve 60 is designed as a simple check valve and the internal combustion engine is operated as a gasoline engine.

Approximately opposite the inlet channel 58, the cylinder 2 has an outlet opening 64, which is covered by a valve disk 66, which is formed with a through opening 68, which covers the outlet opening 64 during an angular range of their rotation or opens. As a result, the outlet opening 64 is temporarily connected to an outlet channel 70 which is formed by a housing extension 72 of the cylinder 2 and on which a shaft 74 of the valve disk 66, which is advantageously arranged completely inside the outlet channel 70, is mounted.

5 shows an end view of the valve disk 66 with the through opening 68 formed therein.

The shaft 74 is advantageously driven by a pinion 76 (FIG. 1) which meshes with one or both disks 34, 36 and is arranged coaxially with a shaft 78 mounted in the motor housing 24 and is connected to the latter in a rotationally fixed manner. The shaft carries a toothed belt pulley 80 which is connected to another via a toothed belt 82 Toothed pulley 84 is connected, which is rotatably connected to the shaft 74 of the valve disk 66. 5, which schematically shows an end view of the entire internal combustion engine without an inlet duct and an outlet duct, denotes a tensioning roller for tensioning the toothed belt 82.

In the following functional description of the internal combustion engine, it is assumed that the internal combustion engine is operated in a two-stroke process as a gasoline engine, with an injection nozzle 88 for injecting fuel in the annular space 52 and a spark plug 90 in the end wall 1.

It is assumed that the piston 4, as shown in FIG. 1, is at its bottom dead center. The piston has then passed over the outlet opening 64. The coordination of the rotation of the valve disk 66 to the movement of the piston 4 is such that the through opening 68 of the valve disk 66 connects the outlet opening 64 to the outlet channel 70, so that burned charge in the working chamber 6 can escape into the outlet channel 70. At the same time, the piston 4 releases the connection of the fresh charge chamber 50 to the working chamber 6 through the passage openings 54 and 56, so that compressed fresh charge is displaced into the working chamber 6 below the piston 4, displacing the burned charge located there.

The piston 4 then moves upwards, passing over the upper passage openings 56 and separating the fresh charge chamber 50 from the working chamber 6. The piston 4 also passes over the outlet opening 64, so that the working chamber 6 is separated from the outlet channel 70. The valve disk 66 closes the outlet opening 64 so that there is no connection between the fresh charge chamber 50 and the outlet channel 70.

During its upward movement, the piston 4 sucks fresh charge into the fresh charge chamber 50, which fuel is metered in a suitable amount as it flows in from the injection nozzle 88. At the same time, the fresh charge contained in the working chamber 6 is compressed and ignited in the region of the top dead center of the piston 4 by means of the spark plug 90. During its downward movement, the piston 4 compresses the fresh charge contained in the fresh charge chamber 50. As soon as the piston 4 passes over the outlet opening 64 before reaching its bottom dead center at the end of the work cycle, this is released from the through opening 68 of the rotating valve disk 66, so that the burned charge escapes into the outlet channel 70 and immediately thereafter as soon as the upper through openings 56 are run over, the compressed fresh charge flows into the working chamber 6.

By designing the outlet opening 64 and the passage opening 56 appropriately, an efficient charge change and a thermodynamically favorable mixing or swirling of the fresh charge and their concentration in front of the spark plug 90 can be achieved, as a result of which low consumption with simultaneously low pollutant emissions is possible. A further advantageous effect is the cooling of the piston 4 caused by the fresh air or fresh charge in the fresh charge chamber.

It is understood that the speed of the valve disk 66 corresponds to the speed of the crank disks. The overlap between the passage opening 68 and the outlet opening 64 can be changed by a device known per se for adjusting the phase between the extension of the valve disk 66 and that of the crank disks, so that optimal operation is adapted to the operating conditions, such as load and speed is achieved.

Furthermore, it goes without saying that the passage openings 56 are arranged and designed in such a way that optimum flushing of the working chamber 6 is achieved.

The internal combustion engine described is also suitable for operation as a diesel engine, the diesel injection nozzle (s) then injecting directly into the working chamber 6. Because the end wall 1 is free of valves, there is optimum design freedom with regard to the arrangement of the injection nozzle (s) and the spark plug (s), and the engine can also be operated as a direct gasoline injector if the injection nozzle 88 injects directly into the working chamber 6.

The engine described has numerous other advantages: As a result of the separation of the crank chamber from the working chamber 6 by the partition 48 and the fresh charge chamber 50 connected to it, the crank chamber and the components arranged in it remain largely cold. This makes it possible to manufacture the parts of the crank mechanism from non-heat-resistant lightweight materials or also from plastic, for example in the form of simpler molded parts, which can save weight and costs.

Furthermore, the low temperatures in the crankcase make it possible to use environmentally friendly oils, for example aqueous dispersions, or to work without lubricants by means of appropriate material combinations, or to use self-lubricating roller bearings or other bearings.

As a result of the low temperatures, an alternator and / or a starter can be integrated directly into the crank mechanism, which saves installation space and components.

The described engine can be modified in many ways:

The double crank drive has the advantage that the shaft 14 is guided linearly. The supporting part 20 does not necessarily have to be arranged on the side of the crank mechanism facing away from the working chamber 6, in which case, however, the advantage of the connecting rods being only subjected to tensile stress is eliminated. Furthermore, the double crank drive, which enables smooth, comfortable engine running, especially at higher speeds, is not absolutely necessary; it is also possible to work with a crankshaft and corresponding intermediate members or drives so that a shaft 14 rigidly connected to the piston 4 can be guided linearly and with a seal through the partition wall 48.

The outlet valve does not necessarily have to be designed as a valve disk 66 in the construction described. This valve disk 66, which can be driven directly electrically, permanently rotating or by a stepping motor, in a simple manner, is particularly advantageous, however, since its structure is simple. The valve disk 66 is not exposed to large axial forces, since it is only subjected to pressure in the fresh charge chamber 50 is acted upon. The pressure in the working chamber 6 is not effective on the valve disk 66, since it opens the way between the exhaust opening 64 and the outlet channel 70 as soon as the piston 4 passes over the outlet opening 64 during its downward movement at the end of a working push. Because of the low axial forces, the valve disc runs with low friction, can be designed with low weight and can be guided axially in a simple manner, for example in its mounting or on its circumference.

To control the charge exchange, an adjustable cover segment 92 (FIG. 1) can be provided, which is formed with openings corresponding to openings 54 and 56, which from a position aligned with openings 54 and 56 into a partially aligned position or openings 54 and 56 closing Position is adjustable. The function of the throttle valve can be relocated to this cover segment. In another embodiment, the openings 54 and 56 can be replaced by grooves which are formed in the inside of the cylinder and form flow channels from the fresh air chamber 50 into the working chamber 6 at the bottom dead center of the piston. The annular space 52 can then be omitted and the fresh air chamber can be connected to the environment through the partition 54.

In a further development of the machine according to the invention, the space between the support part 20 and the cylinder extension 22 can be used as a further compression space with a corresponding design of the support part 20, which is connected to the environment via an inlet valve and via a channel in which a control valve works is connected to the working chamber 6, so that this space can be used as an additional precompression chamber, from which the working chamber 6 can be charged with additional charge. It goes without saying that this additional chamber is only used for charging if the machine requires a corresponding amount of power or torque.

In a further development of the machine described, the supporting part 20 working in the cylinder extension 22 can be used to form an alternator as a linear generator. Furthermore, the support part 20 or a component connected to it can form the piston of an oil pump, via which the piston 4 is cooled through the shaft 14, and so on. FIG. 7 shows an embodiment of the internal combustion engine that is modified compared to FIGS. 1 and 4. In this internal combustion engine, the exhaust valve is designed in a simplified manner in that the valve disk 66 is absent and the exhaust valve is formed only by at least one outlet opening 64, which is preferably slit-shaped with an extension of the slot parallel to the piston movement and is arranged at an appropriate height so that it is separated from the piston 4 when it moves toward bottom dead center, it is preferably passed over or released before the piston passes over or releases the upper passage openings 56 which form the inlet. In this way, an extremely simple, only slot-controlled two-stroke engine is created.

A further advantageous aspect of the two-stroke engine according to the invention with the integrated fresh charge chamber 50 results when fuel is injected directly into the combustion chamber or the working chamber 6 by at least one injection valve according to FIG. 1 being arranged on the left side of the spark plug 90. With such an injection valve, the injection of the fuel (petrol or diesel) can be controlled such that no unburned fuel flows out through the outlet when the charge is changed, so that the efficiency is improved and the pollutant content of the exhaust gas is reduced. The direct injection can be used in both embodiments of the outlet (according to FIG. 4 and according to FIG. 7).

It goes without saying that the engine according to the invention, which operates according to the two-stroke method, can also have a multi-cylinder design.

An advantage of internal combustion engines of the type described, in which the piston is guided linearly and cannot tilt, is that extremely simple, essentially shirtless piston designs are possible.

8 shows an example of such a piston:

The piston, designated overall by 4, has a base body 96, which consists, for example, of metal, advantageously of cast metal. The base body 96 forms the supporting part of the piston 4 and is advantageously with the combustion chamber provided with a coating 98, for example a ceramic part, which is resistant to high temperatures and protects the base body 96 from high peak temperatures. In the example shown, the piston has a depression 100, which is particularly favorable for direct-injection engines.

On the circumferential side, a groove is formed between the base body 96 and the coating 98, in which a piston ring 102 is arranged. As shown, the piston is shirtless and the seal between the inner wall of the cylinder and the piston is provided by the piston ring 102. It will be appreciated that one or more piston rings can be provided. On its side facing away from the coating 98, the base body 96 has a hole into which the shaft 14, which is designed, for example, as a tube, is inserted and fastened therein, for example by screwing or in some other suitable manner.

The piston can be produced, for example, by first prefabricating the coating 98 as a ceramic part, which is then placed in a mold in which the base body 96 is cast. The shaft 14 is then attached to the base body 96 and the piston ring 102 is introduced.

It goes without saying that other manufacturing processes are also possible; for example, the coating can be sintered onto the base body, sputtered on or otherwise applied. Alternatively, the piston can be made entirely of ceramic.

9 shows a cross section through a modified embodiment of a shaft 14. The shaft 14 has two channels 104 and 106, the channel 104 being, for example, a coolant inlet channel and the channel 106 being a coolant outlet channel. The base body 96 in this case has channels connected to the channels 104 and 106, which run close to the surface of the base body 96 on the combustion chamber side and permit effective cooling of the piston. The coolant supply, for example oil supply to the inlet channel 104, follows via a coolant pump, for example an oil pump, which can be designed in a manner known per se. It is understood that the coating 98 is not mandatory. The shaft 14 is advantageously provided with a lubricious coating where it is guided through the partition 48 (FIG. 1).

A piston of the type described can not only be used for the internal combustion engine described above, but is particularly suitable for all internal combustion engines with pistons guided linearly over a shaft.

LIST OF REFERENCE NUMBERS

1 front wall

2 cylinders

4 pistons

6 working chamber

14 shaft

16 crankshaft

18 crankshaft

20 supporting part

22 cylinder extension

24 motor housing

30 disc

32 Write

34 disc

36 disc

38 wave

40 wave

40, wave stub

40 ₂ wave stub

42 external teeth

44 external teeth

46 connecting rod journals

46, connecting rod journal

46 ₂ connecting rod journals

48 partition

50 fresh charge chamber

52 annulus

54 lower passage opening

56 upper passage opening

58 inlet duct

60 inlet valve throttle

outlet opening

valve disc

Durchgangsöffiiung

exhaust port

housing extension

wave

pinion

wave

Timing pulley

toothed belt

Timing pulley

idler

injection

spark plug

covering segment

body

coating

trough

piston ring

channel

Claims

claims

1. Reciprocating piston internal combustion engine, comprising at least one cylinder (2), in which a piston (4) operates to form a working chamber (6), a shaft (14) provided on the piston, which can be moved linearly under sealing by a seal facing away from the working chamber Partition (48) of the cylinder formed on the side of the piston is passed through and connects the piston to a crank mechanism containing a crankshaft, the space between the piston and the partition wall forming a fresh charge chamber (50) which is connected to the environment via an inlet valve device (60) is; an overcurrent device (54, 56) which in the area of the bottom dead center of the

Piston releases an overflow path from the fresh charge chamber into the working chamber, characterized by an outlet valve device (64, 66, 68) which connects the working chamber (6) to an outlet channel (70) in the region of the bottom dead center of the piston (4).

2. reciprocating piston rafting machine according to claim 1, characterized in that the exhaust valve device has an outlet opening (64) formed in the cylinder wall, which is moved over by the piston (4) when it moves to bottom dead center.

3. reciprocating piston internal combustion engine according to claim 2, characterized in that the exhaust valve device has a rotatable about a fixed axis valve disc (66), which sweeps over the outlet opening (64) and has a through opening (68) which in the region of the bottom dead center position of the piston a flow connection between the outlet opening and the outlet channel (70).

4. reciprocating piston internal combustion engine according to claim 3, characterized in that the valve disc (66) is driven in rotation by the crankshaft.

5. reciprocating piston internal combustion engine according to one of claims 1 to 4, characterized in that the shaft (14) of the piston (4) via at least one connecting rod (26,

28) is connected to one of two crankshafts (16, 18) rotating in opposite directions at the same speed.

6. Reciprocating piston internal combustion engine according to claim 5, characterized in that the shaft (14) of the piston (4) passes between the crankshafts (16, 18) and on the side of the crankshafts facing away from the piston (4) with the connecting rods (26, 28) connected is.

7. Reciprocating internal combustion engine according to claim 6, characterized in that the connecting rods (26, 28) can be claimed as predominantly acting on the train in their longitudinal direction

Components are formed.

8. Hubkolbenbrennlα'aftmaschine according to any one of claims 1 to 7, characterized in that the inlet valve (60) is designed as a check valve.

9. reciprocating piston internal combustion engine according to one of claims 1 to 8, characterized in that the reciprocating piston internal combustion engine works according to the two-stroke process.

10. Reciprocating internal combustion engine according to claim 9, characterized in that fuel is injected into the working chamber (6) in such a way that no unburned fuel gets into the outlet channel.

11. Piston, in particular for a reciprocating piston internal combustion engine according to one of claims 1 to 9, characterized by a base body (96), on the side facing the crank mechanism, a shaft (14) is rigidly attached.