Reciprocating piston internal combustion engine

Abstract

A reciprocating piston internal combustion engine includes at least one first, one second and one third cylinder and has a crank mechanism having a crankshaft, which is rotatably mounted in a crankcase, having a first, a second and a third crankpin. A first connecting rod having a first piston for the first cylinder is allocated to the first crankpin. A second connecting rod having a second piston for the second cylinder is allocated to the second crankpin. A third connecting rod having a third piston for the third cylinder is allocated to the third crankpin. The crankpins are arranged successively in an axial direction of the crankshaft, wherein the cylinders are arranged in a fan shape.

Claims

1. A reciprocating piston internal combustion engine, comprising: first, second, and third cylinders; a crank mechanism with a crankshaft mounted rotatably in a crankcase; first, second, and third crankpin journals, wherein the first crankpin journal is assigned a first connecting rod with a first piston for the first cylinder, the second crankpin journal is assigned a second connecting rod with a second piston for the second cylinder, the third crankpin journal is assigned a third connecting rod with a third piston for the third cylinder, the first, second, and third crankpin journals are arranged sequentially behind one another in an axial orientation of the crankshaft, the second cylinder is immediately adjacent to both the first and third cylinders, relative to a first axial end of the crankshaft the first cylinder is closest to the first axial end, and the first, second, and third cylinders are arranged like a Japanese-style hand held folding fan, such that the second cylinder is disposed in a space between the first cylinder and the third cylinder when view from the first axial end of the crankshaft.

2. The reciprocating piston internal combustion engine according to claim 1, further comprising: one bearing point for the crankshaft being provided, in each case, between the first, second, and third crankpin journals.

3. The reciprocating piston internal combustion engine according to claim 2, wherein adjacent ones of the first, second, and third cylinders form a cylinder angle between 20 and 90 crank angle.

4. The reciprocating piston internal combustion engine according to claim 3, wherein at least two cylinder angles are unequal.

5. The reciprocating piston internal combustion engine according to claim 3, further comprising: a mass balancing shaft drivable by the crankshaft, the mass balancing shaft being oriented parallel to the crankshaft.

6. The reciprocating piston internal combustion engine according to claim 1, wherein adjacent ones of the first, second, and third cylinders form a cylinder angle between 20 and 90 crank angle.

7. The reciprocating piston internal combustion engine according to claim 6, wherein at least two cylinder angles are unequal.

8. The reciprocating piston internal combustion engine according to claim 1, further comprising: a mass balancing shaft drivable by the crankshaft, the mass balancing shaft being oriented parallel to the crankshaft.

9. The reciprocating piston internal combustion engine according to claim 1, wherein the reciprocating piston internal combustion engine is mounted in a single track vehicle.

10. The reciprocating piston internal combustion engine according to claim 9, wherein the crankshaft is installed transversely with respect to a driving direction of the single track vehicle.

11. The reciprocating piston internal combustion engine according to claim 1, wherein the reciprocating piston internal combustion engine is mounted in a motorcycle.

12. The reciprocating piston internal combustion engine according to claim 11, wherein the crankshaft is installed transversely with respect to a driving direction of the motorcycle.

13. The reciprocating piston internal combustion engine according to claim 1, wherein relative to the first cylinder, the second and third cylinders are incrementally more distant from the first cylinder along a radial orientation of the crankshaft.

14. A reciprocating piston internal combustion engine, comprising: a crankcase defining first, second, and third cylinders; and a crankshaft mounted rotatably in the crankcase, wherein the crankshaft has first, second, and third crankpin journals, each crankpin journal is connected to a respective connecting rod and piston, each piston being disposed in a different cylinder, relative to a first axial end of the crankshaft the first crankpin journal is closest to the first axial end, the second cylinder is immediately adjacent to both the first and third cylinders, and a longitudinal axis of each cylinder extends along a different radial direction of the crankshaft such that the first, second, and third cylinders are arranged like a Japanese-style hand held folding fan, wherein the second cylinder is disposed in a space between the first cylinder and the third cylinder when view from the first axial end of the crankshaft.

15. The reciprocating piston internal combustion engine according to claim 14, further comprising: one bearing point for the crankshaft being provided, in each case, between the first, second, and third crankpin journals.

16. The reciprocating piston internal combustion engine according to claim 15, wherein adjacent ones of the first, second, and third cylinders form a cylinder angle between 20 and 90 crank angle.

17. The reciprocating piston internal combustion engine according to claim 16, wherein at least two cylinder angles are unequal.

18. The reciprocating piston internal combustion engine according to claim 16, further comprising: a mass balancing shaft drivable by the crankshaft, the mass balancing shaft being oriented parallel to the crankshaft.

19. The reciprocating piston internal combustion engine according to claim 14, wherein the reciprocating piston internal combustion engine is mounted in at least one of a single track vehicle and a motorcycle.

20. The reciprocating piston internal combustion engine according to claim 19, wherein the crankshaft is installed transversely with respect to a driving direction of the at least one of a single track vehicle and a motorcycle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a front view of a reciprocating piston internal combustion engine according to an embodiment of the invention;

(2) FIG. 2 is a plan view of the reciprocating piston internal combustion engine according to the embodiment of the invention;

(3) FIG. 3 is a side view of the reciprocating piston internal combustion engine according to the embodiment of the invention; and

(4) FIG. 4 is a front view of a single track vehicle having a reciprocating piston internal combustion engine according to the embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) In the following text, the same designations apply for identical components in FIGS. 1 to 4.

(6) FIG. 1 shows a front view of a reciprocating piston internal combustion engine having at least a first, a second and a third cylinder 1, 2, 3. A crank mechanism 4 is shown without an encasing crankcase, with the result that the crank mechanism is freely visible. The crank mechanism 4 consists of a crankshaft 5, which is mounted rotatably in the crankcase (not shown), with a first, a second and a third crankpin journal 6, 7, 8. Here, the first crankpin journal 6 is assigned a first connecting rod 9 with a first piston for the first cylinder 1, the second crankpin journal 7 being assigned a second connecting rod 11 with a second piston for the second cylinder 2, and the third crankpin journal 8 being assigned a third connecting rod 13 with a third piston for the third cylinder 3. Since the pistons are mounted such that they can be moved in a reciprocating manner in the respective cylinders, they are concealed by the cylinders 1, 2, 3. Three cylinder heads and cylinder covers which are assigned to the cylinders 1, 2, 3, under which in each case a visible valve gear is arranged, are not provided with a designation in the figures.

(7) As can be seen clearly in FIG. 1, the crankpin journals 6, 7, 8 are arranged behind one another or next to one another in an axial orientation of the crankshaft 5. On account of the axial orientation of the crankpin journals 6, 7, 8, the cylinders 1, 2, 3 are arranged in a fan-shaped manner according to the invention, as a result of which different cylinder angles (shown in FIG. 3) can be realized structurally. Furthermore, an output 14, consisting, inter alia, of a gear mechanism (which is not shown in greater detail) is arranged on the crankshaft 5 in order to output the power generated by the reciprocating piston internal combustion engine. Fan-shaped is understood to mean that each cylinder lies in a plane which is parallel to the further planes which are formed by the other cylinders. One example for this is, for example, Japanese hand fans.

(8) Furthermore, in each case one bearing point 12 is provided for the crankshaft 5 between the crankpin journals 6, 7, 8 for optimum rigidity of the crankshaft and the crankcase. Only one bearing point 12 is designated in FIG. 1. Bearing points can also be provided for the crankshaft in front of and behind the crankpin journals 6, 8.

(9) FIG. 2 shows a plan view of the reciprocating piston internal combustion engine from FIG. 1. The fan-shaped arrangement of the cylinders 1, 2, 3 can also be seen clearly in FIG. 2.

(10) FIG. 3 shows a side view of the reciprocating piston internal combustion engine. Two cylinder angles are illustrated in FIG. 3, between the adjacent cylinders 1, 2 and 2, 3. Moreover, the camshaft drives which are not provided with a designation can also be seen in FIG. 3. The adjacent cylinders 1, 2 and 2, 3 form a cylinder angle which preferably lies between 20 and 90 crank angle. In a further exemplary embodiment, cylinder angles of different size can also be realized between the cylinders 1, 2 and 2, 3. The ignition sequence can be influenced positively by said design variant, with the result that a different sound can be produced.

(11) In a further preferred exemplary embodiment, a mass balancing shaft (not shown in FIGS. 1 to 4) can be driven by the crankshaft 5 and is oriented parallel to the crankshaft 5. By way of the mass balancing shaft, for example of the first order, the smooth running of the reciprocating piston internal combustion engine can be influenced positively, that is to say the NVH behavior can be improved considerably.

(12) FIG. 4 shows a front view of a single track vehicle 13, in which the reciprocating piston internal combustion engine according to the invention is installed. As shown in FIG. 4, the crankshaft 5 can preferably be installed transversely with respect to a driving direction of the single track vehicle 13. The single track vehicle is preferably a motorcycle or a moped.

(13) In comparison with other radial reciprocating piston internal combustion engines, the invention therefore makes a narrower cylinder angle possible in the case of the existing cylinder offset. The minimum cylinder angle is dependent on the cylinder offset, and the spacing of the crankpin journals 6, 7, 8 on the crankshaft 5.

(14) Moreover, on account of the possible cylinder angles , the invention makes it possible to implant a W3 reciprocating piston internal combustion engine virtually in the installation space of a V-twin reciprocating piston internal combustion engine. The overall width increases only in a non-critical range.

(15) Accordingly, the cylinder angle of a W4 reciprocating piston internal combustion engine is only insubstantially greater than in the case of a V4 reciprocating piston internal combustion engine.

(16) The sound of a V-twin reciprocating piston internal combustion engine can likewise be replicated by way of a reciprocating piston internal combustion engine of this type; the sound can even be designed to be somewhat fresher.

LIST OF DESIGNATIONS

(17) 1 First cylinder 2 Second cylinder 3 Third cylinder 4 Crank mechanism 5 Crankshaft 5 Crankshaft axis 6 First crankpin journal 7 Second crankpin journal 8 Third crankpin journal 9 First connecting rod 10 Second connecting rod 11 Third connecting rod 12 Bearing point 13 Single track vehicle 14 Output

(18) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.