WO1998023855A1

WO1998023855A1 - Reciprocating engine

Info

Publication number: WO1998023855A1
Application number: PCT/EP1997/006547
Authority: WO
Inventors: Heinz Winger
Original assignee: Heinz Winger
Priority date: 1996-11-27
Filing date: 1997-11-24
Publication date: 1998-06-04

Abstract

A reciprocating engine contains at least one piston (2) guided into a cylinder (1). Each piston (2) is connected with two connecting rods (6, 6') via a preferably linearly displaceable piston rod (3) and a connecting rod joint (5, 5'). These connecting rods engage with a crankshaft journal (7, 7') of two crankshafts (8, 8'), which are coupled via a gearing (10, 10', 11) for synchronous rotation in opposite directions. Such a reciprocating machine is designed to improve the conversion of the pressure curve in the cylinder into a torque curve at the crankshaft, thus achieving greater efficiency. It is proposed that the connecting rods (6, 6') are designed so short that the travel of the connecting rod joints (5, 5') passes through a plane (E), which forms a common tangential plane of the orbits of the crankshaft journals (7, 7').

Description

Piston engine

The invention relates to a piston engine according to the features specified in the preamble of claim 1.

A piston engine is known from German published patent application DE 27 46 476 A1, in particular an internal combustion engine, which contains at least one cylinder with a piston and a piston rod moving in a straight line. A transmission link is connected to the piston rod, to which at least two connecting rods are connected via a connecting rod joint. The other ends of the connecting rods are coupled to crank shafts via crank pins, which are connected via synchronized rotation gears in opposite directions of rotation. The lengths of the connecting rods are comparatively large. The efficiency of such a piston engine is significantly influenced by the fact that the pressure curve in the cylinder, especially when it is designed as an internal combustion engine, cannot be converted into an optimal torque curve on the crankshaft.

Furthermore, from the German published patent application DE 31 29 028 A1 an internal combustion engine with two counter-rotating crankshafts is known, which are coupled via a transmission. Within the piston, a common connecting rod joint is provided for two connecting rods, which are each coupled to one of the two crankshafts via crank pins. Due to the design, the length of the connecting rods is greater than the stroke of the piston, which is linearly displaceable in the cylinder. Finally, a drive device for two shafts driven in the opposite direction by a piston is known from German patent 105 605. In this device, two connecting rods or handlebars are coupled on the one hand to the piston and on the other hand to two crank disks. The crank disks, whose shafts are arranged coaxially, are coupled by means of a bevel gear. The connecting rod joints of the connecting rods are arranged inside the piston and the connecting rods have a considerably greater length than the diameter on which the crank pins of the crank disks rotate.

The object of the invention is therefore to design a piston engine of the type mentioned in such a way that a more favorable conversion of the pressure curve in the cylinder into the torque curve on the crankshaft and thus in particular an increased efficiency is achieved.

This object is achieved according to the features specified in claim 1.

Due to the short connecting rods, the piston engine according to the invention is characterized by an optimized conversion of the pressure curve in the cylinder into the torque curve of the crankshaft. Two connecting rods are provided, which are articulated on a transmission link. The transmission link is used primarily to compensate for lateral forces, so that the design effort, in particular with regard to guides and bearings, can be considerably reduced. The connecting rod bearings are arranged on the transmission element, and expediently at a distance substantially the same as the center distance of the two crankshafts. If the piston is in the top dead center position, the connecting rods are aligned essentially parallel to one another or they have a slight deviation or a predetermined small angle to the piston axis, in particular if they are designed with a predetermined low negative set. In the case of a piston engine with negative setting, the angle between the connecting rods is increased starting from the top dead center during the working stroke of the piston. The transmission link is coupled to the piston rod. The coupling can take place via a joint or bearing. In a special embodiment, the transmission element is firmly connected to the piston rod, in particular in one piece in such a way that the transmission element and the piston rod form a single component. The at least two connecting rods are made so short that the path of the connecting rods leads through a plane which at least approximately through the upper or lower Dead center of the circular path of the crankshaft journal runs. According to the invention, this plane is the common tangential plane at the rotating circles of the crank pins of the two crankshafts. Furthermore, this plane is parallel to the plane which is defined by the two crankshaft axes. Due to the short design of the at least two connecting rods according to the invention, the pivoting angle of the connecting rod is considerably increased in comparison with previously known arrangements in the working stroke, with the result that an increased proportion of the potential energy of the piston is converted into kinetic energy of the crankshaft mass. The higher proportion of kinetic energy of the piston stroke is transmitted to the crankshaft mass in accordance with the respective swivel angle of the connecting rod and thus increases the kinetic energy of the crankshaft mass. In comparison with crank drives, which enable comparatively small pivoting angles of the connecting rods, a significant improvement in efficiency, in particular> 10% and beyond, is achieved by the piston engine according to the invention. It should also be emphasized that the efficiency increases expediently with increasing push rod ratio, that is to say crank radius in relation to the length of the connecting rod. The transmission of a relatively large piston stroke via relatively short connecting rods, which for constructional reasons only have to be a little longer than half the piston stroke, leads to a very favorable torque curve on the crankshaft and thus to a significantly increased efficiency compared to conventional comparable piston engines.

The connecting rods are designed according to the invention so short that the smallest distance between the centers of the two connecting rod bearings to the plane in which the crankshaft axes lie is less than half the diameter or as the radius of the circle on which the centers of the crank pins move. The connection of the connecting rods to the connecting rod joints connected to the piston, preferably via a piston rod or another transmission element, makes it possible to make the connecting rods as short as is desired for an optimal torque curve of the crankshaft. In contrast to crosshead machines, which are only designed as relatively slow-running piston engines and in which the transverse forces occurring at the crosshead have to be absorbed, the piston engine according to the invention compensates with two connecting rods each, which are connected to one another via the connecting rod joints, the transverse force components that occur there, so that no crosshead guide is required. The piston engine according to the invention enables mutual support by means of the common transmission element for the two connecting rods. No additional guides or support devices are required to direct the forces from the reciprocating piston to the two short connecting rods arranged in pairs. In an expedient manner, the machine is designed with a predetermined negative set, whereby, above all, stabilization with regard to lateral vibrations is achieved. The negative setting is specified in such a way that at the top dead center the connecting rods are at an angle to the plane running through the piston or the cylinder. Starting from the top dead center, the angle between the two connecting rods is increased during the working stroke of the piston. It was recognized that, with the same potential energy on the piston, machines with a negative setting give a higher kinetic energy to the crankshaft than in the case of machines with a positive setting, in which the angle between the connecting rods becomes smaller at the beginning of the working stroke. In addition, it was recognized that a parallel adjustment of the crankshafts for the purpose of changing the cubic capacity is made possible with the piston engine according to the invention in a restricted configuration, so that the piston engine can be operated with different fuels.

The condition previously taken into account in the design of piston engine, which corresponds to the mean effective pressure multiplied by the stroke volume of the effective power, cannot be applied to the piston engine according to the invention. This property is due to the different working speed of the piston. With an increasing swivel angle of the connecting rod in the working stroke, an increased proportion of the kinetic energy of the crankshaft can be supplied from the potential energy.

The two crankshafts are preferably connected to one another via a gear transmission, each of the two crankshafts having a spur gear which are in engagement with one another. Instead of the gearwheels mentioned, other gear links such as chain gearboxes, toothed belt drives, hydraulic gearboxes or other gearboxes can also be used, which enable the two crankshafts assigned to each cylinder to run synchronously with opposite directions of rotation.

Further advantageous embodiments of the invention are the subject of further dependent claims. Exemplary embodiments of the invention are illustrated below, which are shown in the drawing. Each shows in a schematic representation:

Fig. 1 A piston engine with two parallel crankshafts and one

Transmission link between two connecting rods, in the top dead center position,

2 the piston engine according to FIG. 1 in the bottom dead center position,

Fig. 3 shows a special embodiment in which the transmission link and

Piston rod form a single component,

4 shows an embodiment with two pistons arranged side by side,

5, 6 enlarge a preferred coupling of the transmission element according to FIG. 4 in two sectional planes rotated by 90 ° with respect to one another.

The piston engine shown in FIGS. 1 and 2 contains a cylinder 1 in which a piston 2 is movably received along a piston axis 1 a. It is, for example, an internal combustion engine. A piston rod 3 is connected to the piston 2 and is guided out of the cylinder 1 in a piston rod guide 4 and moves in a straight line. The separate piston rod guide can also be dispensed with.

The piston rod 3 is connected at its end facing away from the bottom of the piston 2 via a transmission member 14 by means of connecting rod joints 5, 5 'to two connecting rods 6, 6'. The connecting rod joints or connecting rod bearings 5, 5 'are arranged on the transmission member 14, which is connected in an articulated manner to the piston rod 3 by means of a bolt 15. Each connecting rod 6 or 6 'engages a crankshaft journal 7 or 7' of two crankshafts 8 or 8 '. The length L of the connecting rods 6 and 6 'is only slightly larger than the turning circle radius R of the center of the crank pin 7 and 7', which corresponds to half the piston stroke by design. In an expedient embodiment, which is explained below, the piston rod 3 and the transmission member 14 are rigidly connected to one another, so that the articulated connection by means of a bolt is omitted. The piston rod 3 and the transmission member 14 advantageously form a single component, with an articulated connection with the piston being present.

Another alternative embodiment is indicated in the lower half of FIG. 1 with dash-dotted lines. Here, with respect to the crankshaft plane K, a further cylinder 1 ′ is arranged on the other side than the first cylinder 1. A further transmission element 14 'is coupled to the piston rod 3' thereof and two further connecting rods are connected to the crankshaft pins 7 and 7 '. In this embodiment, two connecting rods are thus articulated on each of the two crankshaft pins 7 and 7 '.

It is also possible for two connecting rods of two oppositely directed cylinders to engage the crankshaft journal. The crankshafts 8, 8 'belonging to a plurality of cylinders 1 can be connected to one another to form a multi-cylinder machine by means of transmission elements such as gears or gears.

Fig. 2 shows that in the bottom dead center position, the connecting rod joints 5, 5 'are below the plane E, which is also defined as a common tangent to the two trajectories of the crankshaft pins 7 and 7'.

The length L of the connecting rods, that is the distance between the center of the connecting rod bearing 5 and the center of the crank pin bearing 7, is short in comparison with known constructions. The ratio of the radius R to the length L, which ratio is also referred to as the push rod ratio, is greater than 0.5 according to the invention. It is essential that the middle of the connecting rod joint 5, 5 'reaches the area below the plane E or on the side facing away from the piston 1 with respect to the plane E during the working stroke. The plane E is the common tangent to the rotating circles of the two crankshaft journals 7 and 7 'and it is arranged essentially parallel to the plane K in which the two crankshaft axes 9, 9' lie.

Starting from the top dead center position, which is shown in Fig. 1 and in which the two connecting rods 6, 6 'are parallel to the piston rod 3, the two connecting rods 6 and 6' due to the opposite rotational movements in the direction of Crankshaft journal 7 and 7 'pressed. The force exerted by the piston rod 3 in the direction of the plane K is divided in the direction of the two connecting rods 6 and 6 'according to a force parallelogram, lateral forces which occur being compensated according to the invention by means of the transmission element 14. The particularly high lateral or transverse forces of the connecting rods 6, 6 'with respect to the longitudinal axis 1 a in the case of short connecting rods are introduced into the crankshafts in a particularly advantageous manner. Because of the short connecting rods according to the invention, their swivel angles become larger in the working stroke and an enlarged portion of the potential energy of the piston is converted into kinetic energy of the crankshaft mass. This leads to a significant increase in the efficiency of the machine.

After turning the crankshafts by 90 ° from top dead center, the crankshaft pins are in the common plane of the two crankshaft axes. It is important according to the invention that in this position the angle between the connecting rod and the cylinder axis 1 a is greater than 45 degrees. The swivel angle is expediently large at least 50 angular degrees when half the working stroke is reached.

Deviating from the example shown in FIGS. 1 and 2, it can be provided that the piston rod extends beyond the crankshaft axes and the connecting rods are subjected to tension. In this way it is achieved according to the invention that the combustion pressure in the upper dead center area is kept over a larger angular range, so that the combustion in the cylinder can take place more completely and thus the working pressure is increased.

The piston engine, which is only shown schematically, can be designed, for example, as an internal combustion engine in the form of an Otto engine, a diesel engine and in a two-stroke or four-stroke type. Furthermore, in the context of this invention, the piston engines can also be steam engines, air pressure or gas pressure engines and can be operated as a combustion engine with gas, gasoline, diesel oil, bio-oil (rapeseed), gas or hydrogen.

For a version as a two-stroke internal combustion engine, the linear guidance of the piston rod 6 proves to be particularly advantageous because the cylinder space located in the cylinder 1 below the piston 2 can be sealed in a simple manner in order to charge a cylinder for the two-stroke flushing of the distribution chamber located above the piston 2 to build. 3 shows a special embodiment of the piston engine according to the invention, in which the piston rod 3 is integrated in the transmission member 14 or is designed as an arm thereof. The transmission member designed in this way as a single component with an integrated piston rod has two arms 16, 17 with the connecting rod joints 5, 5 '. In this embodiment, the piston rod is designed as a short arm, which is arranged in the extension of the two arms 16, 17. The arms 16, 17 are each arranged at an angle 18 to the piston axis 1 a, which is less than 90 °. The forces exerted by the piston 2 via the integrated piston rod 3 from above as a result of the downward inclination of the arms 16, 17 towards the crankshafts are essentially introduced and transmitted as pressure forces in the arms 16, 17, with disadvantageous bending forces on the Transmission member 14 avoided or at least significantly reduced.

The crankshafts 8, 8 'with their axes parallel to each other are connected to the others via a gear transmission and each contain a spur gear 13 or 13', which are in engagement with one another and bring about a synchronous operation of the two crankshafts 8, 8 'in the opposite directions of rotation . The output can take place on one of the two crankshafts 8 and 8 '. The transmission member 1 integrated with the piston rod into a single component enables the transmission of the piston forces to the connecting rod joints 5, 5 ', without additional, other supports being required and thus the entire play of forces between the piston and the crankshaft journal taking place.

The cylinder 1 or its cylinder liner contains a recess or a slot 21 for the transmission member 14, which is indicated by dashed lines. In the top dead center position, the transmission member 14 is largely in this recess 21. The recess 21 is arranged and designed such that in the bottom dead center position, that is to say when rotating through 180 ° out of the position shown, the piston 2 or its Piston rings, a secure seal in the cylinder 1 only schematically indicated here. Correspondingly, the housing 20 receiving the crankshafts 8, 8 'also contains a recess 22 in which the transmission member with the connecting rod joints 5, 5' are at least partially located in the top dead center position. Due to the slotted recess 21 and the housing recess 22 for the transmission member 16, a considerable reduction in the overall height of the piston engine is achieved. In a particularly expedient manner, the cross section of the arms 16, 17 is, starting from the connecting rod joints 5, 5 'in the direction of Piston axis 1 a enlarged, so that high stability and strength is ensured with little use of materials.

An alternative embodiment is indicated in FIG. 3 with dash-dotted lines 23, 24. If the connecting rods 6, 6 'are of a restricted design or arrangement, the connecting rod joints 5 and 7 or 5' and 7 'lie on the dash-dotted lines 23 or 24 or on lines parallel to them in the top dead center position. The particularly expedient negative setting ensures stabilization with regard to lateral vibrations, the pivoting angle 25 with respect to the piston axis being specified in accordance with the requirements.

In a special embodiment of the invention, the distance 26 between the crankshafts or crankshaft axes 9, 9 ′ which are parallel to one another can be changed. This makes it possible to change the cubic capacity in a preferred manner, in order to make it possible above all to adapt to different fuels of the design as a drive motor. Instead of a direct coupling of the crankshafts 8, 8 'by means of the spur gears mentioned, a gear arrangement is provided which nevertheless ensures the opposite synchronous running of the two crankshafts 8, 8' when the distance 26 is changed.

FIG. 4 shows a further special embodiment with two parallel pistons 2, 2 ′ lying next to one another, which are coupled to a common transmission element 14 in the manner shown. The piston axes 1 a and 1 ′ a expediently run through the crankshafts 8, 8 ′, as a result of which a particularly favorable course of forces is achieved. This parallel arrangement of the pistons keeps the load on the transmission element low. As can be seen, in this double-piston machine the common transmission member 14 with the two integrated piston rods is essentially U-shaped. In this embodiment too, a recess 21 is provided in the cylinder 1 and a recess 22 in the housing 20, into which the transmission member 14 engages in the top dead center position, which in turn reduces the overall height to a minimum.

5 and 6 show an expedient development of the articulation of the piston rod 3 'on the piston 2' by means of a pin guide 27. This pin guide 27 is designed in such a way that changes in length which result in the direction of the double arrow 28, for example as a result of temperature changes or tolerances the without corresponding forces are transmitted to the piston 2 '. The pin guide 27 enables lateral relative movements in the direction of the double arrow 28 of the transmission member 14 with respect to the piston 2 '. On both sides of the bolt guide 27 there is sufficient play or a gap 29 to enable expansion or tolerances to be compensated for.

reference numeral

Cylinder a piston axis

piston

Piston rod

Piston rod guide, 5 'connecting rod joint, 6' connecting rod, 7 'crankshaft journal, 8' crankshaft, 9 'crankshaft axis, 13' spur gear

transmission member

Joint, 17 arm

angle

casing

Recess / slot in 1

Housing recess, 24 dash-dotted line

Swivel angle

Distance between 9, 9 '

Bolt guide

Double arrow

Gap / play

Claims

claims

1. Piston engine with at least one piston (2) guided in a cylinder (1), which is connected to two connecting rods (6, 6 ') via a preferably linearly movable piston rod (3) and a connecting rod joint (5, 5'), which each engage a crankshaft journal (7, 7 ') of two crankshafts (8, 8'), the two crankshafts (8, 8 ') being synchronized by a gearbox (10, 10', 1 1; 13, 13 ') Rotation in opposite directions of rotation are coupled, characterized in that the connecting rods (6, 6 ') are articulated on a transmission member (14) which is connected to the piston rod (3) and that the connecting rods (6, 6') are of such a short design are that the path of the connecting rod joints (5, 5 ') runs through a plane (E) which forms a common tangential plane of the circular paths of the crankshaft journals (7, 7').

2. Piston engine, in particular according to claim 1, characterized in that the transmission member (14) on the piston rod (3) is articulated, in particular via a bolt (15), or that the transmission member (14) and the piston rod (3) rigid with each other are connected and are preferably formed as a component.

3. Piston engine according to claim 1 or 2, characterized in that in the top dead center position, the connecting rods (6, 6 ') articulated on the transmission member (14) are arranged substantially parallel to one another or a set, preferably negative set, with a pivot angle (25). exhibit.

4. Piston engine according to one of claims 1 to 3, characterized in that the connecting rods (6, 6 ') are only longer than half the piston stroke by a small predetermined amount, preferably a maximum of 20%, in particular a maximum of 10%.

5. Piston engine, in particular according to one of claims 1 to 4, characterized in that the connecting rods (6, 6 ') are made so short that the smallest distance between the centers of the connecting rod joints (5, 5') when the piston (2) is moving. ) to the plane (K) of the crankshaft axes (8, 8 ') is less than the radius (R) of the circle on which the centers of the crankshaft pins (7, 7') can be moved.

6. Piston engine according to one of claims 1 to 5, characterized in that the two crankshafts (8, 8 ') are arranged axially parallel and that the cylinder axis (1 a) in a plane of symmetry (8a) of the two crankshafts (8, 8') lies.

7. Piston engine according to one of claims 1 to 6, characterized in that it is operated with a negative setting, the pivot angle (25) of the two connecting rods (6, 6 ') increases at least at the beginning of the working stroke and / or that the pivot angle (25) of the respective connecting rods (6, 6 ') is at least 50 ° large when the middle of the working stroke is reached.

8. Piston engine according to one of claims 1 to 7, characterized in that the piston rod (3a) on the plane (K) of the two crankshafts (8, 8 ') extends and that the connecting rods (6, 6') in the working stroke Train can be claimed.

9. Piston engine according to one of claims 1 to 8, characterized in that two connecting rods (6, 6 ') act on the crankshaft journal (7, 7') in the opposite direction of two oppositely arranged cylinders (1, 1 ').

10. Piston engine according to one of claims 1 to 9, characterized in that the transmission member are arranged two down to the plane of the crank shaft axes (9, 9 ') at an angle (18) <90 °.