WO2022262905A1

WO2022262905A1 - Reciprocating piston engine

Info

Publication number: WO2022262905A1
Application number: PCT/DE2022/100444
Authority: WO
Inventors: Michael Aschaber; Rupert Baindl
Original assignee: Neander Motors Aktiengesellschaft
Priority date: 2021-06-16
Filing date: 2022-06-14
Publication date: 2022-12-22

Abstract

The invention relates to a reciprocating piston engine having a crankcase, which accommodates at least one crankshaft, and a cylinder housing (10), said cylinder housing (10) being a one-piece cast part which accommodates at least one cylinder liner (20), at least one cylinder head (30) and at least one OHV valve controller having a valve, a rocking lever and a push rod, and the camshaft co-operating with the OHV valve controller being an in-block camshaft disposed at the level of the cylinder liner (20) and accommodated by the crankcase.

Description

RECIPROCATING ENGINE

The invention relates to a reciprocating piston engine with a crankcase accommodating at least one crankshaft.

As a bearing for the crankshaft, the crankcase is an important part of combustion engines. The casing, which is usually made as a cast part, not only assumes the function of bearing the crank shaft, but also forms the liners for accommodating the cylinders.

An engine with two counter-rotating crankshafts, which are each connected to a common piston by means of a connecting rod, has advantages in terms of noise and vibration behavior due to the greatly reduced lateral guiding force of the piston and the ability to compensate due to the counter-rotating crankshaft. However, the position of the crankshafts means that a longer piston rod is required, so that the height of the engine - from the crankshaft axis to the cylinder head - is increased compared to conventional engines with only one crankshaft.

The object of the invention is therefore to further develop an engine, in particular an engine with two counter-rotating crankshafts, so that it has the lowest possible overall height.

According to the invention, this object is achieved by the reciprocating engine having the features of claim 1 . The dependent claims reflect advantageous refinements of the invention.

The basic idea of the invention is to combine the cylinder liner, which is usually arranged in the crankcase, with the cylinder head in a housing, referred to below as the cylinder housing, so that a cylinder head gasket that is conventionally required can be omitted. Accordingly, the cover plates that are usually provided for closed-deck crankcases on both the cylinder head and the crankcase are no longer required, so that the engine height and weight are lower can be saved. This is particularly advantageous in engines with two crankshafts rotating in opposite directions, which, due to the connection of one piston to each of the two crankshafts, require rather long connecting rods and thus contribute to a rather large overall height. Finally, a more uniform cylinder deformation is given in the construction according to the invention due to the lack of cylinder head screws.

The reduction in height is achieved on the one hand by using a camshaft with a push rod underneath and on the other hand by integrating the valve spring space, cylinder head and push rod space in a common housing part. On the one hand, this reduces the timing drive to a minimum - on the other hand, there is no need for an overhead camshaft drive wheel that would counteract a low overall height.

The integration of the parts in the one-piece cylinder housing requires a comparatively complex cast part, but significantly reduces further processing steps, so that overall production can be expected to be simpler. Geometrically, the usually required material wall thicknesses on the cylinder head plate and the camshaft housing plate (each at least 10 mm) are omitted. The accumulations of material that are nevertheless required have been shifted to the area in which they do not add any additional heights—namely to the area of the connecting rod—between the cylinder head and the crankshaft, since the connecting rod and the crank mechanism determine the height in this area.

According to the invention, a reciprocating piston engine with a crankcase accommodating at least one crankshaft and a cylinder housing is proposed, the cylinder housing being a one-piece casting accommodating at least one cylinder liner, at least one cylinder head and at least one OHV valve controller having a valve, a rocker arm and a push rod. In particular, the cylinder housing is arranged above the crankcase and is connected to it by means of suitable connecting means, e.g.

According to a first preferred embodiment, the camshaft cooperating with the OHV valve control is a camshaft located below, which is particularly preferably Height of the cylinder liner is arranged. The camshaft cooperating with the OHV valve control is most preferably accommodated by the crankcase.

The crankcase also preferably has a ram which is resiliently mounted against the cylinder housing by means of a ram spring and cooperates with the ram rod of the OHV valve control, so that the inertial forces of the ram can be absorbed by the cylinder housing and are not transmitted to the ram rod. The cylinder housing thus forms the abutment of the tappet spring, which is braced when the cylinder housing is screwed to the crankcase. On its side facing away from the crankcase, the cylinder housing is preferably closed by means of a valve cover, the push rod of the OHV valve control being insertable from the side of the valve cover into a push rod holder designed to accommodate a push rod and being removable therefrom. This means that the push rod can be easily removed upwards for repair or maintenance work without having to disassemble the engine.

The reciprocating piston engine is further preferably designed such that the crankcase and the cylinder housing have a first sealing surface arranged in the area of the cylinder liners and a second sealing surface arranged in the area of the camshaft cooperating with the overhead valve control. The sealing surfaces are arranged in two different planes in the direction of the overall height of the motor, i.e. in the vertical direction or along its longitudinal axis, with the first sealing surface and the second sealing surface being arranged horizontally offset from one another and the first sealing surface being arranged below the second sealing surface.

The outlet port of the at least one cylinder head is preferably arranged laterally on the cylinder housing, with it being particularly preferred that the outlet port of the at least one cylinder head is arranged between two push rod mounts each designed to accommodate a push rod.

The at least one cylinder liner preferably accommodates a cylinder which is connected by means of two connecting rods to a respective crankshaft arranged in the crankcase, with the crankshafts being set up in particular to rotate in opposite directions. Especially for this case, it is also advantageous if the at least one cylinder liner in the area of the first sealing surface extends at least one in the longitudinal direction of the cylinder liner has extending radial recess, wherein most preferably one of the radial recess arranged opposite further radial recess is provided. These recesses are used for lateral deflection of the connecting rods connected to the piston, which can be made shorter than conventionally due to this special design and thus also contribute to a low overall height.

As an additional advantage, it is proposed that the piston, which is movably arranged in the at least one cylinder liner, with a ring section having a piston head, a piston skirt arranged adjacent to the ring section and having two pin bushings, and two connecting rods connecting the piston to the two crankshafts by means of a pin each inserted in a pin bushing design, wherein the diameter of the piston skirt in the longitudinal direction of the pin bushings is 40% to 70% of the diameter of the piston crown.

The advantage of the preferably used piston is that a very light and compact piston can be provided for use in the cylinder housing according to the invention with a low overall height. Since the oscillating masses are directly included in the mass of the mass balance, a reduction in the oscillating masses has a double effect, so that smooth running is achieved. At the same time, a short piston skirt increases the ability to twist and thus the ability to accommodate manufacturing tolerances. At the same time, the associated reduced wear leads to an improved service life.

The diameter of the piston skirt is preferably 50% to 65% and particularly preferably 50% to 60% of the diameter of the piston head in the longitudinal direction of the pin bushings.

The height of the piston skirt is preferably 15% to 45% and particularly preferably 30% to 40% of the diameter of the piston head.

Furthermore, it is preferably provided that the distance between the centers of the pin bushings is 25% to 40% and particularly preferably 30% to 37% of the diameter of the piston head. The piston is in particular made of steel or aluminum and can be specially made by means of a metal-based additive process. Furthermore, the piston can have a cooling channel for its cooling, which is connected to a line providing a coolant.

Finally, with regard to the piston, it is particularly preferably provided that the piston has a mirror-symmetrical design.

According to a further preferred embodiment, it is provided that the OHV valve control has a rocker arm connecting a valve to a push rod and a tappet arranged opposite the rocker arm on the push rod, as well as a camshaft acting on the tappet, the tappets being designed as hydraulic tappets.

With this OHV valve control, i.e. a valve control with "overhead valves" (overhead valves, hanging valves), a hydraulic valve clearance compensation is integrated into the tappet on the camshaft side. Because the inertia force compensation is preferably taken over by the tappet spring, the other elements of the valve train can be made particularly light without additional inertial forces having to be taken over by the tappet or the valve clearance compensation by the valve spring, and thus have an overall positive effect on the low-height engine out.

Because of this preferred configuration, particularly in combination with the preferred design of the piston, higher speeds can be achieved far above the speeds that are conventional for push-rod engines. The inertial forces in the valve train are essentially decisive for this. Due to the preferred configuration of a relatively short push rod and its design as a tube, it has been possible in the present case to reduce the mass of the push rod. On the other hand, a hydraulic valve clearance compensation element could be integrated into the tappet for valve clearance compensation. The resulting increased inertial forces are preferably compensated by the plunger spring right at the plunger.

To compensate for the higher inertia forces that result from the design of the tappet as a hydraulic tappet, the hydraulic tappet is preferably resiliently mounted in the direction of the camshaft by means of a tappet spring supported on the cylinder housing. With that in particular the disadvantage avoided that otherwise the valve spring would have to be made stronger.

A preferably space-saving design is achieved for the case in which the plunger spring is arranged in sections surrounding the bumper and is partially accommodated by the plunger housing of the plunger with its end opposite the bearing formed by the crankcase.

Basically, it is provided that the movable piston of the tappet faces the end of the push rod opposite the rocker arm and the valve clearance compensation takes place between the hydraulic tappet and the push rod and not, as is usual, between the hydraulic tappet and the camshaft. In this case, the movable piston of the tappet is particularly preferably designed as a ball pressure pin.

According to a further preferred embodiment, the bumper is designed as a tube, so that on the one hand the weight of the valve train can be reduced overall.

On the other hand, the hollow space of the bumper designed as a tube is preferably designed to communicate with the oil line of the tappet, so that the oil pressure building up at least over the length of the hollow space can be used to reduce the valve clearance without having a negative effect on the masses to be moved. For this purpose, the cavity of the bumper, which is designed as a tube, is designed to communicate with the oil line of the tappet.

In addition, the design of the bumper as a continuous tube has the advantage that the connection between bumper and rocker arm can also be lubricated by means of the oil guided in the bumper.

Finally, the valve is resiliently mounted in the direction of the rocker arm by means of a valve spring supported on the cylinder housing, so that overall valve control can be created that is advantageous in terms of noise behavior, the occurrence of vibrations and the ability to compensate.

The valve control is particularly suitable in connection with a reciprocating engine, which has two counter-rotating crankshafts, each by means of a Connecting rod are connected to a common cylinder. Because of the position of the two crankshafts, there is a need for a longer piston rod and thus—in comparison to conventional engines with one crankshaft—an increased height of the engine, which can now be compensated for by the valve control according to the invention. With this type of reciprocating piston engine, the space required to construct this special engine can be further reduced and at the same time the already existing smooth running can be further improved.

The invention is explained in more detail below with reference to an exemplary embodiment which is illustrated in the accompanying drawings and is of particularly preferred design. Show it:

1 shows a perspective view from above of a particularly preferably designed cylinder housing;

FIG. 2 shows a perspective view from below of the particularly preferred embodiment of the cylinder housing shown in FIG. 1;

3 shows a front view of a particularly preferred embodiment in detail;

Fig. 4 is a side view of the embodiment shown in Fig. 3;

5 shows a perspective view of a piston of the internal combustion engine designed according to the invention; and

6 shows the schematic structure of a particularly preferably designed valve control in a partially sectioned side view.

FIG. 1 shows a perspective view of a particularly preferably configured cylinder housing from above, with FIG. 2 showing a perspective view of the particularly preferably configured cylinder housing illustrated in FIG. 1 from below. The cylinder housing 10 is part of a stroke piston engine, not shown in detail, which has two counter-rotating crankshafts accommodated in the crankcase, not shown, which are each connected to a common cylinder by means of a connecting rod, the cylinders each having a cylinder liner 20 are recorded. It can be seen that the cylinder liners 20 in their lower region, in which the cylinder housing 10 with the crankcase (not shown) arranged underneath forms a first sealing surface 40, a radial recess 25 extending in the longitudinal direction of the cylinder liner 20 and one of the radial Recess 25 have further radial recess 25 arranged opposite. These recesses 25, 25 of the cylinder liner 20 are used for lateral deflection and thus for partial accommodation of the connecting rods connected to the crankshaft and are used to reduce the general overall height of the engine.

The monolithic cylinder housing 10 is designed as a one-piece casting and, in addition to the cylinder liners 20, has the cylinder heads 30 and a plurality of OHV valve controls, each consisting of a valve, a rocker arm and a push rod. The camshaft cooperating with the OHV valve controls is a camshaft located below, which is arranged at the level of the cylinder liner 20 . The camshaft, which cooperates with the OHV valve control, is accommodated in the crankcase.

In particular, the crankcase accommodates a tappet that is spring-mounted against the cylinder housing and cooperates with the pushrod of the OHV valve control, the crankcase and cylinder housing 10 having a second sealing surface 50 in the area of the camshaft that cooperates with the OHV valve control.

On the upper side of the cylinder housing, the cylinder housing 10 is closed on its side facing away from the crankcase by means of a valve cover, the push rod of the OHV valve control being insertable from the side of the valve cover into a push rod holder designed to accommodate a push rod and being removable from this. The cylinder head outlets 30 are each arranged laterally on the cylinder housing 10, with some cylinder head outlets 30 being arranged in a space-saving manner between two push rod receptacles 60 each designed to accommodate a push rod.

Finally, the receptacles 70 of the axle fastening the rocker arms of the OHV valve control can also be seen in FIG. 1 (cf. also FIG. 6).

FIG. 3 shows a front view of a particularly preferred exemplary embodiment, of which essentially only the piston 100 is shown in detail. As is known, the piston 100 is movably arranged in a cylinder liner (not shown) of an internal combustion engine and has a ring part 130 having a piston crown 120 and a piston skirt 140 arranged adjacent to the ring part 130 . The piston skirt 140 has two pin bushings, each of which is designed to receive a pin 150, with the aid of which a connecting rod 160 is fastened to the piston 100 in each case. The end of the connecting rods opposite the piston 100 is connected to a respective crankshaft (not shown).

As FIG. 4 shows in a side view of the detail shown in FIG. 3, the diameter of the piston skirt 140 in the longitudinal direction of the pin bushings is approximately 55% of the diameter of the piston head 120 and is therefore in the particularly preferred range of between 50% and 60%. In the example shown, the height of piston skirt 140 is approximately 35% and thus in the range of 30% to 40% of the diameter of piston crown 120

FIG. 5 also shows a perspective view of the piston 100 of the internal combustion engine configured according to the invention, without the further elements shown above, in particular the connecting rods and the bolts, being drawn in.

Finally, FIG. 6 shows the schematic structure of a particularly preferably configured valve control in a partially sectioned side view.

The valve control 200 consists of a valve 220 with a push rod 230 connecting rocker arm 240 and the rocker arm 240 opposite to the push rod 230 arranged tappet 250. The acting on the camshaft 260 acting tappet 250 is as Hydraulic tappet is formed, which is resiliently mounted in the direction of the camshaft 260 in particular by means of a tappet spring 270 supported on the cylinder housing 10 in the region of the second sealing surface 50 . It can also be seen that the plunger spring 270 is arranged partially surrounding the push rod 230 and is also partially received by the plunger housing 252 of the plunger 250 with its end opposite the bearing formed by the cylinder housing 10 . The movable piston 254 of the tappet 250 is designed as a ball pressure pin and faces the end of the push rod 230 opposite the rocker arm 240 .

The push rod 230 is designed as a tube, with the cavity 232 of the tube being designed to communicate with the oil line of the ram 250 . Finally, it can be seen that the valve 220 is resiliently mounted in the direction of the rocker arm 240 by means of a valve spring 280 supported on the cylinder housing 10 .

Claims

EXPECTATIONS

1. Reciprocating piston engine with a crankcase accommodating at least one crankshaft and a cylinder housing (10), the cylinder housing (10) having at least one cylinder liner (20), at least one cylinder head (30) and at least one OHV having a valve, a rocker arm and a push rod - The valve control is a one-piece casting, the camshaft cooperating with the OHV valve control is a camshaft located at the level of the cylinder liner (20) and supported by the crankcase.

2. Reciprocating piston engine according to claim 1, characterized in that the crankcase has a plunger which is resiliently mounted against the cylinder housing (10) by means of a plunger spring and cooperates with the pushrod of the OHV valve control.

3. Reciprocating piston engine according to one of the preceding claims, characterized in that the crankcase and the cylinder housing (10) have a first sealing surface (40) arranged in the area of the cylinder liners (20) and a second sealing surface arranged in the area of the camshaft cooperating with the overhead valve control Has sealing surface (50).

4. Reciprocating engine according to claim 3, characterized in that the at least one cylinder liner (20) in the region of the first sealing surface (40) has at least one in the longitudinal direction of the cylinder liner (20) extending radial recess (25).

5. Reciprocating piston engine according to claim 4, characterized by one of the radial recess (25) arranged opposite further radial recess (25).

6. Reciprocating engine according to one of claims 3 to 5, characterized in that the first sealing surface (40) and the second sealing surface (50) are arranged in different planes.

7. Reciprocating piston engine according to one of the preceding claims, characterized in that the cylinder housing (10) is closed on its side facing away from the crankcase by means of a valve cover, the push rod of the OHV valve control being guided by the valve cover into a push rod designed to accommodate a push rod Rod holder (60) can be used and removed from this.

8. Reciprocating piston engine according to one of the preceding claims, characterized in that the outlet channel of the at least one cylinder head (30) is arranged laterally on the cylinder housing (10).

9. Reciprocating piston engine according to one of the preceding claims, characterized in that the outlet channel of the at least one cylinder head (30) is arranged between two push rod receptacles (60) each designed to accommodate a push rod.

10. Reciprocating piston engine according to one of the preceding claims, characterized in that the at least one cylinder liner (20) accommodates a cylinder which is connected by means of two connecting rods (160) to a respective crankshaft arranged in the crankcase, the crankshafts being arranged to rotate in opposite directions to one another.

11. Reciprocating piston engine according to Claim 10, characterized by a piston (100) which is movably arranged in the cylinder liner (20) and has a ring part (130) having a piston head (120), a piston skirt (140) which is arranged adjacent to the ring part (130) and has two pin bushings ) and two connecting rods (160) connecting the piston (100) to the two crankshafts by means of a bolt (150) each inserted in a pin bush, the diameter of the piston skirt (140) in the longitudinal direction of the pin bushes being 40% to 70% of the diameter of the piston crown (120) is.

12. Reciprocating piston engine according to claim 11, characterized in that the diameter of the piston skirt (140) in the longitudinal direction of the pin bushings is 50% to 65% of the diameter of the piston crown (120).

13. Reciprocating piston engine according to one of claims 11 and 12, characterized in that the diameter of the piston skirt (140) in the longitudinal direction of the pin bushings is 50% to 60% of the diameter of the piston head (120).

14. Reciprocating engine according to one of claims 11 to 13, characterized in that the height of the piston skirt (140) is 15% to 45% of the diameter of the piston crown (120).

15. Reciprocating engine according to one of claims 11 to 14, characterized in that the height of the piston skirt (140) is 30% to 40% of the diameter of the piston head (120).

16. Reciprocating piston engine according to one of claims 11 to 15, characterized in that the distance between the centers of the pin bushings is 25% to 40% of the diameter of the piston head (120).

17. Reciprocating piston engine according to one of claims 11 to 16, characterized in that the distance between the centers of the pin bushings is 30% to 37% of the diameter of the piston head (120).

18. Reciprocating engine according to one of claims 11 to 17, characterized in that the piston (100) is made of steel or aluminum.

19. Reciprocating piston engine according to claim 18, characterized in that the piston (100) is manufactured by means of a metal-based additive process.

20. Reciprocating engine according to one of claims 11 to 19, characterized in that the piston (100) has a cooling channel.

21. Reciprocating engine according to one of claims 11 to 20, characterized in that the piston (100) is mirror-symmetrical.

22. Reciprocating piston engine according to one of the preceding claims, characterized in that the OHV valve control has a rocker arm (240) connecting a valve (220) to a push rod (230) and a rocker arm (240) opposite to the push rod (230). tappet (250) and a camshaft (260) acting on the tappet (250), the tappets (250) being designed as hydraulic tappets.

23. Reciprocating piston engine according to claim 22, characterized in that the tappets (250) are resiliently mounted in the direction of the camshaft (260) by means of a tappet spring (270) supported on the crankcase.

24. Reciprocating piston engine according to one of claims 22 and 23, characterized in that the plunger spring (270) partially surrounds the push rod (230) and is partially received by the plunger housing (252) of the plunger (250) with its end opposite the bearing formed by the crankcase is.

25. Reciprocating engine according to one of claims 22 to 24, characterized in that the movable piston (254) of the tappet (250) faces the rocker arm (240) opposite end of the push rod (230).

26. Reciprocating piston engine according to one of claims 22 to 25, characterized in that the movable piston (254) of the tappet (250) is designed as a ball pressure pin.

27. Reciprocating engine according to one of claims 22 to 26, characterized in that the push rod (230) is designed as a tube.

28. Reciprocating engine according to claim 27, characterized in that the hollow space (232) of the push rod (230) designed as a tube is designed to communicate with the oil line of the tappet (250).

29. Reciprocating piston engine according to one of claims 22 to 28, characterized in that the valve (220) is resiliently mounted in the direction of the rocker arm (240) by means of a valve spring (280) supported on the crankcase.