METHOD AND APPARATUS FOR ADJUSTMENT OF CAMSHAFT

SEGMENT FOR CAMSHAFT OF ENGINE

Technical Field

The present invention relates to a camshaft segment for a camshaft of a gas engine. In particular, the invention relates to a camshaft segment for fine- tuning a camshaft segment orientation. The present disclosure also relates to a camshaft. In addition, the present disclosure relates to a method for adjusting the orientation of a camshaft segment. Further, the present disclosure relates to a tool for adjusting the orientation of two camshaft segments relative to each other.

Technological Background

The operation of internal combustion engines (ICEs) may cause the generation of undesirable emissions, which may be exhausted to the environment or require additional efforts and costs for exhaust gas purification.

One way of mitigating undesirable emissions both chemically and in volume is to increase ICE efficiency for example by adjusting the actuation timing of the engine valves. For example, the actuation timing of the intake and exhaust valves may be modified to implement a variation on the Otto cycle for gas engines. One example is the so-called Miller cycle, which may include a configuration, in which the intake valves of the engine are held open during a portion of the compression stroke of the piston, thereby reducing emissions and improving the overall ICE efficiency. The engine valves in an internal combustion engine are typically driven by a cam arrangement that is operatively connected to the crankshaft of the engine. The rotation of the crankshaft results in a corresponding rotation of a cam that drives one or more cam followers. The movement of the cam followers results in the actuation of the engine valves. However, while valve actuation timing adjustments may provide efficiency benefits, these actuation timing adjustments may also result in detrimental engine performance if the timing is not accurately executed. Presently, in Miller combustion processes, tolerances in camshaft geometry may deviate several crank angle degrees from the desired point in time. Slight deviations in cam geometry may lead to improper actuation of a camshaft, hence, leading to engine performance impairment. As an example, the delayed start of compression may lead to cylinder temperatures insufficient to support good combustion and startability. Thus, to obtain the greatest gains from implementing a variation on conventional valve actuation timing, an ICE requires precisely actuating cams. Because the shape of the cam is fixed, the cam position may only be changed by adjusting the camshaft as a whole or mounting the cam differently.

The camshaft segment, the camshaft, the adjustment method and the tool of the present disclosure solve one or more problems set forth above.

Summary of the Invention

Starting from the prior art, it is an objective to provide a simple, cost-effective and reliably adjustable camshaft for an internal combustion engine, in particular for a gas engine to be operated at a Miller cycle. This objective is solved by means of a camshaft segment for a camshaft of a gas engine with the features of claim 1, a camshaft with the features of claim 6, a gas engine with the features of claim 11, an adjustment method with the features of claim 12 and a tool with the features of claim 16. Preferred embodiments are set forth in the present specification, the Figures as well as the dependent claims.

Accordingly, a camshaft segment for a camshaft of the gas engine is provided. The camshaft segment comprises a shaft having at least one cam mounted thereto and a flange comprising a first flange recess and a second flange recess and at least one adjustment device provided in one of the first and second flange recesses. The adjustment device is configured such that it provides an adjustment abutment which protrudes longitudinally outwardly from the flange. The adjustment device is configured such that the adjustment abutment is adjustable in an angle of the shaft rotation. Furthermore, a camshaft is provided, comprising a first camshaft segment and two adjustment devices, each providing an adjustment abutment, wherein each of the camshaft segments comprises a flange having a flange recess via which the flanges may be interlocked by means of first and second adjustment abutments of the first and second adjustment devices. In addition, a gas engine is provided comprising a camshaft segment and/or a camshaft. The gas engine may be configured to be operated at a Miller combustion cycle.

Process-wise, an adjustment method for adjusting the orientation of a first camshaft segment relative to a further camshaft segment coupled thereto in an angle of rotation is provided. The method comprises the steps of detecting a target orientation displacement between the first camshaft segment and the second camshaft segment, calculating, based on the detected target orientation displacement, a target adjustment, at which the first and second adjustment devices need to be adjusted in order to reach the target orientation between the first camshaft segment and the second camshaft segment, and adjusting the first and second adjustment devices such that the target orientation displacement between the first camshaft segment and the second camshaft segment is reached.

Furthermore, a tool for adjusting the orientation of a first camshaft segment relative to a second camshaft segment in an angle of a shaft rotation is provided. The tool comprises a first tool body which is mounted to the first camshaft segment and which comprises a first and a second adjustment device and a second tool body mounted to the second camshaft segment comprising a first and second abutment. The first and second tool bodies are configured such that the first and second abutments can be brought into contact with the first and second adjustment device respectively.

Brief Description of the Drawings

The present disclosure will be more readily appreciated by reference to the following detailed description when being considered in connection with the accompanying drawings in which:

Fig. 1 schematically shows a camshaft segment for a camshaft of a gas engine according to an embodiment in a perspective view;

Fig. 2A schematically shows the camshaft segment for a camshaft of Figure 1 in a first side view;

Figs. 2B and 2C schematically illustrate the underlying principle of adjusting the orientation displacement on the basis of Fig. 2A;

Fig. 3 schematically shows a camshaft segment according to another embodiment; Fig. 4 schematically shows a camshaft for gas engine according to an embodiment in a perspective view;

Fig. 5 schematically shows the camshaft of Fig. 4 in a side view;

Fig. 6 schematically shows a tool for adjusting the orientation of a first camshaft segment relative to a second camshaft segment in a first embodiment;

Fig. 7 schematically shows a tool for adjusting the orientation of a first camshaft segment relative to a second camshaft segment according to another embodiment; and

Fig. 8 schematically shows a flow diagram depicting a method according to an embodiment.

Detailed Description of Preferred Embodiments

In the following, the invention will be explained in more detail with reference to the accompanying figures. In the Figures, like elements are denoted by identical reference numerals and repeated description thereof may be omitted in order to avoid redundancies.

The present disclosure is generally directed towards a camshaft segment for a camshaft of a gas engine that allows a fine adjustment of cams in a camshaft. Being mounted on a camshaft segments, the fine adjustment of cams may be achieved by fine adjustment of the camshaft segments. Fine adjustment of the cams to actuate cylinder stations correctly may thus be achieved by adjusting the orientation of cams or cam shaft segments respectively. To this end, the teaching of the present disclosure suggests attaching separate camshaft elements together in an adjustable way. The fine adjustment of the camshaft segments can either be achieved via a tool or a screw.

Thereto, the present invention and its underlying principles are explained exemplary for a camshaft segment for a camshaft of a gas engine.

Figure 1 schematically shows a camshaft segment 10 for a camshaft of a gas engine according to an embodiment in a perspective view. The camshaft segment 10 may thus be a part of a camshaft of a gas engine (not shown in Figure 1). The camshaft segment 10 may comprise a shaft 12 having at least one cam 110 (shown in dashed lines) mounted thereto and a flange 14 comprising a first flange recess 16 and a second flange recess 18. The camshaft segment 10 may further comprise at least one adjustment device 20 provided in one of the first and second flange recesses 16, 18. The adjustment device 20 may be configured such that it provides an adjustment abutment 22 which protrudes longitudinally outwardly from the flange 14. The adjustment device 20 may be configured such that the adjustment abutment 22 is adjustable in an angle a of the shaft rotation.

According to the present disclosure, the term adjustment device relates to a component or element which allows adjusting the orientation of the camshaft segment relative to another structure, for example another camshaft device, which is not shown in Figure 1. The camshaft segment 10 may have an axis of rotation revolving about the longitudinal axis L. To this end, the angle a of the shaft rotation may revolve about the longitudinal axis L. The adjustment abutment 22, which may protrude longitudinally outwardly from the flange 14 therefore may protrude in a direction along the longitudinal axis L.

As shown in the schematically illustrated magnification of Figure 1, the adjustment device 20 may be configured such that it provides an adjustment abutment 22 which may protrude longitudinally outwardly from the flange 14 by a protrusion AL. The magnified illustration also shows that the adjustment device 20 may be configured such that the adjustment abutment 22 may be adjustable in an angle a of the shaft rotation. By adjusting the adjustment device 20, its adjustment abutment 22 may be displaced by an orientation displacement Da. To this end, adjusting the adjustment device 20 may be understood as changing the distance of the adjustment abutment 22 to a cut-out abutment 26. As a consequence, by changing the distance of the adjustment abutment 22, the cam 110 mounted on the shaft 12 of the camshaft segment 10 may be displaced about the angle a of the shaft rotation. Thereby, the orientation displacement Da determines the degree of the angular displacement of the camshaft 10 and also of the cam 110. The adjustment device 20 may be a screw or comprise a screw.

According to the embodiment shown in Figure 1, the adjustment device 20 may be a screw which may comprise a screw head 21 on which the abutment 22 is provided. Turning the screw at a given screw angle f, for example by a predetermined screw angle displacement, or adjustment rotation, Df will cause a displacement of the abutment 22, hence will change the abutment displacement Da. Thereby, the correlation between the screw angle f and the abutment displacement Da may be based on geometric dependencies such as a screw winding step and may be used for fine-tuning the orientation of the camshaft segment 10 relative to another camshaft 10. Turning back to the main illustration of Figure 1, the flange 14 may comprise a first adjustment device 20 provided in the first flange recess 16 and a second adjustment device (not shown) provided in the second flange recess 18. The first flange recess 16 and the second flange recess 18 may be provided opposite to each other on the flange 14. Alternatively, only one flange recess may comprise an adjustment device. Also, instead of being provided opposite to each other on the flange 14, any other arrangement is possible in principle.

More specifically, the first flange recess 16 and the second flange recess 18 may consist of a cut-out of the flange 14 configured such that the remaining structure of the flange provides a first cut-out abutment 26 in the first flange recess 16 and a second cut-out abutment 27 in the second flange recess 18. According to the embodiment shown in Figure 1, the first and second cut-out abutments 26, 27 may extend along a plane E running through the longitudinal axis L of the camshaft segment 10. In the shown embodiment, the recesses 26, 27 are provided asymmetrically to the longitudinal axis L, such that on one side of the plane E, the flange side “behind” the plane E as illustrated in Figure 1, a full half flange 14 of the camshaft segment 10 may be provided. Likewise, on the other side of the plane E, the flange side “in front” of plane E as illustrated in Figure 1, the flange 14 may comprise the two recesses 16, 18. Further, the first adjustment device 20 may be received in the flange recess 16 in a direction perpendicular to the cut-out abutment 26.

Likewise, the second adjustment device (not shown in Figure 1) may be received in the flange 14 in a direction perpendicular to the surface of the cut-out abutment 27. The camshaft segment 10 may further comprise a plurality of through-holes 28 which may be provided on a protruding circumference 30 of the flange 14. The term protruding circumference 30 may refer to a circumference on the protruding part of flange 14 having a greater diameter than the shaft 12 of the camshaft segment 10. Not shown in Figure 1 are fastening means in the shape of bolts or screws which may be placed inside the through-holes 28 to fasten the camshaft segment 10 to another camshaft segment.

To this end, any fastening means extending through the through- holes 28 must be configured such that when placed inside the trough holes 28, a sufficient wiggle room, or margin, in the direction of the angle a of the shaft rotation is present, in order to at least allow setting the orientation displacement Da by the first and second adjustment devices 20, 22. Setting the orientation displacement Da may then be achieved by turning the screw head 21 by a screw angle displacement, or adjustment rotation, Df corresponding to the orientation displacement Da.

Figure 2 schematically shows the camshaft segment 10 for a camshaft as shown in Figure 1 in a first side view which corresponds to a viewpoint along the longitudinal axis L. To this end, where applicable, the same principles discussed in the context of Figure 1 may also apply to Figure 2. The camshaft segment 10 may comprise a shaft 12 having at least one cam 110 (shown in dashed lines) mounted thereto and a flange 14 comprising a first flange recess 16 and a second flange recess 18. The camshaft segment 10 may further comprise at least one adjustment device 20, which is provided in the first flange recess 16. The adjustment device 20 may be configured such that it provides an adjustment abutment 22 which protrudes longitudinally outwardly from the flange 14. The adjustment device 20 may be configured such that the adjustment abutment 22 is adjustable in an angle a of the shaft rotation, for example by an orientation displacement Da.

As can be seen by the illustration provided in Figure 2, adjusting the adjustment device 20 may be understood as changing the distance of the adjustment abutment 22 to a cut-out abutment 26 to set an abutment displacement Da. Both adjustment devices 20 and 24 are shown, which each may comprise a screw head 21. The flange 14 may comprise a first adjustment device 20 provided in the first flange recess 16 and a second adjustment device 24 provided in the second flange recess 18. The first flange recess 16 and the second flange recess 18 may be provided opposite to each other on the flange 14. Alternatively, only one recess may comprise an adjustment device. Also, instead of being provided opposite to each other on the flange 14, any other arrangement is possible in principle.

More specifically, the first flange recess 16 and the second flange recess 18 may consist of a cut-out of the flange 14 configured such that the remaining structure of the flange 14 provides a first cut-out abutment 26 in the first flange recess 16 and a second cut-out abutment 27 in the second flange recess 18.

According to the embodiment shown in Figure 1 and Figure 2, the first and second recess abutments 26, 27 may extend along a plane E running through the longitudinal axis L of the camshaft segment 10. In the shown embodiment, the recesses 16, 18 may be provided asymmetrically to the longitudinal axis L, such that on one side of the plane E, a full half flange 14 of the camshaft segment 10 may be provided and on the other side of the plane E, the flange 14 may comprise the two recesses 16, 18. Further, the first adjustment device 20 may be received in the flange 14 in a direction perpendicular to the surface of the cut-out abutment 26. Likewise, the second adjustment device 24 may be received in the flange 14 in a direction perpendicular to the surface of the cut-out abutment 27.

The camshaft segment 10 may further comprise a plurality of through-holes 28 which are provided on a protruding circumference 30 of the flange 14. The term protruding circumference 30 may refer to a circumference on the flange 14 which has a greater diameter than the shaft 12 of the camshaft segment 10. Not shown in Figure 2 are fastening means in the shape of bolts or screws which may be placed inside the through-holes 28 to fasten the camshaft segment 10 to another camshaft segment. To this end, the fastening means must be configured such that when placed inside the trough holes 28, a sufficient wiggle room in the direction of the angle a of the shaft rotation is present, in order to at least allow setting the abutment displacement Da. Setting the displacement Da may then be achieved by turning the screw head by a screw angle displacement Df corresponding to the abutment displacement Da.

Figures 2B and 2C schematically illustrate the underlying principle of how the orientation displacement Da may be set by means of the first and second adjustment devices 20, 24. In the present embodiment, the first and second adjustment devices 20, 24 may each have a screw head 21. Figure 2B may represent the starting point prior to the adjustment. Turning the screw head 21 of the first adjustment device 20 clockwise at a given screw angle f, for example until a predetermined adjustment rotation Df is reached, will lead to a displacement of the adjustment abutment 22. The first adjustment abutment 22 is now closer to the first cut-out abutment 26. Likewise, turning the screw head 21 of the second adjustment device 24 counterclockwise at the same screw angle f, for example until a predetermined adjustment rotation Df is reached, will lead to a displacement of the adjustment abutment 24. The second adjustment abutment 25 is now further away from its associated second cut-out abutment 27. The result of these adjustments is shown in Figure 2C. As shown, although the first camshaft section 10 remains in the same position, the first and second adjustment abutments 22, 25 are now oriented in an angular displacement Da. The structure abutting the first and second adjustment abutments 22, 25 is not part of the camshaft segment 10. Figure 3 schematically shows a camshaft segment according to another embodiment. Where applicable, the same principles discussed in the context of Figures 1, Figures 2A-2C may also apply to Figure 3.

According to this embodiment, only an excerpt of a flange 14 of a camshaft segment 10 is shown. Not shown is the rest of the camshaft segment for a camshaft of a gas engine, comprising a shaft having at least one cam mounted thereto. Only the first flange recess 16 is shown, however, the flange 14 may also comprise a second flange recess 18. The camshaft segment 10 according to the embodiment shown in Figure 3 may comprise at least one adjustment device 20 provided in one of the first and second flange recesses 16. In this embodiment, the first flange recess 16 may have the shape of a through-hole. The adjustment device 20 may be configured such that it provides an adjustment abutment 22 which protrudes longitudinally outwardly from the flange 14.

The adjustment device 20 may be configured such that the abutment 22 is adjustable in an angle a of the shaft rotation. The latter may be achieved by a cone-section of the adjustment device 20 which may provide a different adjustment abutment 22 depending on the longitudinal position of the adjustment device 20.

Similar to the embodiment shown in Figures 1-2C, the camshaft segment 10 of the present embodiment may have an axis of rotation revolving about the longitudinal axis L. To this end, the angle a of the shaft rotation revolves about the longitudinal axis L. Further, the adjustment abutment 22, which may protrude longitudinally outwardly from the flange 14 therefore protrudes in a direction defined by the longitudinal axis L. As shown in the schematically illustrated magnification of Figure

1, the adjustment device 20 may be configured such that it provides an adjustment abutment which protrudes longitudinally outwardly from the flange 14 by a protrusion AL. By adjusting the adjustment device 20, its adjustment abutment 22 may be displaced by an orientation displacement Da. To this end, adjusting the adjustment device 20 may be understood as changing the distance of the adjustment abutment 22 to a cut-out abutment 26 following the principles shown in Figures 2B and 2C above.

Accordingly, the adjustment device 20 may be a screw or a bolt comprising a screw. In the embodiment shown in Figure 3, the screw may comprise a screw head 21 on which the abutment 22 is provided. Turning the screw at a given screw angle f, for example by a predetermined adjustment rotation Df, will lead to a displacement of the adjustment abutment 22, hence will change the abutment displacement Da. Thereby, a correlation between the screw angle f and the abutment displacement Da may be used for fine-tuning the orientation of the camshaft segment 10 relative to another camshaft 10.

The flange 14 may comprise a first adjustment device 20 provided in the first flange recess 16 and a second adjustment device (not shown) provided in the second flange recess (not shown). The first flange recess 16 and the second flange recess may be provided opposite to each other on the flange 14.

Alternatively, only one recess may comprise an adjustment device. Also, instead of being provided opposite to each other on the flange 14, any other arrangement is possible in principle.

More specifically, the first flange recess 16 and the second flange recess may consist of a through-hole provided longitudinally within the flange 14, configured such that the through-hole boundary of the flange 14 provides a first cut-out abutment 26 in the first flange recess 16 and a second recess abutment in the second recess.

The camshaft segment 10 may thus further comprise a plurality of further through-holes which are provided on a protruding circumference 30 of the flange 14. The term protruding circumference 30 may refer to a circumference on the flange 14 which has a greater diameter than the shaft 12 of the camshaft segment 10. Not shown in Figure 3 are fastening means in the shape of bolts or screws which may be placed inside the through-holes to fasten the camshaft segment 10 to another camshaft segment. To this end, the fastening means must be configured such that when placed inside the trough holes 28, a sufficient wiggle room in the direction of the angle a of the shaft rotation is present, in order to at least allow setting the abutment displacement Da. Setting the displacement Da may then be achieved by turning the screw head by a screw angle displacement Df corresponding to the abutment displacement Da.

Figure 4 schematically shows a camshaft for gas engine according to embodiment in a perspective view. The camshaft 100 shown in Figure 4 may be based on the embodiments shown in Figures 1-2C of the present disclosure.

To this end, where applicable, the same principles discussed in the context of Figures 1-2C may also apply to Figure 4.

More specifically, the camshaft 100 may comprise a first camshaft segment 10 and the second camshaft segment 11 and two adjustment devices 20, 24. Thereto, the first adjustment device may provide an adjustment abutment 22 and the second adjustment device 24 may provide a second adjustment abutment 25. Each of the camshaft segments 10, 11 may comprise a flange 14, 15 having a flange recess 16, 18, 161, 181 via which the flanges 14, 15 may be interlocked by means of the first and second adjustment abutments 22, 25 of the first and second adjustment devices 20, 24.

In other words, the first and second camshaft segments 10, 11 may have similar features. Regarding the two flange recesses 16 and 18 provided on the first flange 14, 15, and the two flange recesses 161, 181 provided on the second flange 15, adjacent flange recesses 16, 161 and 18, 181 may be complementary to their counterpart provided on the adjacent flange in order to allow interlocking the first flange 14 relative to the second flange 15.

To this end, the camshaft 100 may comprise a total of two adjustment devices 20, 21. The first and second flanges 14, 15 may be configured such that each adjustment device 20, 21 may be provided in one flange recess 16, 18 of flange 14 and may provide longitudinally protruding abutments 20, 22 for engaging in the corresponding flange recesses 161, 181 of the other flange 15, which in this case may not comprise any adjustment devices 20, 21 in their flange recesses 161, 181. In other words, two complementary recesses, namely the recesses adjacent to each other when the two flanges are brought together, may share one adjustment device which is configured to engage with the complementary recess via its longitudinally protruding abutment. Therefore, only one of two complementary recesses may comprise the adjustment device 20, 22.

To this end, the first and second adjustment devices may be provided on the first flange 14 of the first camshaft segment 10 or the second camshaft segment 11. Alternatively, according to an embodiment not shown in figure 3, the first adjustment device 10 may be provided on the first flange 14 of the first camshaft segment 10 and the second adjustment device 22 may be provided on the second camshaft segment 11.

The first and second adjustment devices 20, 22 may be configured such that their first and second abutments 26, 27 may be adjustable in an angle a of a shaft rotation, such that the first flange 14 and the second flange 15 may be adjusted angularly relative to each other.

To this end, the first adjustment device 20 and the second adjustment device 22 may each comprise a screw. Thereby, a complementary rotation of the screws by an adjustment rotation DF of 30° may correspond to an orientation displacement Da between the first and second camshaft segments 10, 11 of 0.1°.

Further, each of the flanges 14, 15 may comprise a plurality of congruent through-holes 28 which may be provided on a circumference 30 of the flanges 14, 15. Each of the through-holes 28 may have a diameter greater than a diameter of a fastening Rod running through said through-holes 28. More precisely, in each through hole 28 difference in diameter between the through hole 28 and the fastening rod may provide a margin of 0.1°. Thereby, even at an orientation displacement Da between the first and second camshaft segments 10,

11 of 0.1°, fastening the two flanges 14, 15 by the fastening rod may still be achieved. Figure 5 schematically shows the camshaft of Figure 4 in a first side view. To this end, where applicable, the same principles discussed in the context of Figures 1, 2 and 4 may also apply to Figure 5. According to this view of the present embodiment, it can be seen how the first adjustment device 20 and the second adjustment device 24 engage with the abutments of their corresponding recesses 16, 17. To this end, the first adjustment device 20 and the second adjustment device 24 are both provided on the first camshaft segment 10. Both adjustment devices 20, 24 may be configured such, that their adjustment abutments 22, 25 may be adjustable in an angle a of the shaft rotation. Both adjustment devices 20, 22 may comprise a screw which is configured such that a portion of a screw head may provide the abutment 22, 25. The first adjustment device 20 a be provided in a first flange recess 16 and the second adjustment device 24 may be provided in the second flange recess 18. The first flange recess 16 and the second flange recess 18 may be provided opposite to each other on the flange 14.

Both the first flange recess 16 and the second flange recess 18 may consist of a cut-out of the flange 14 configured such that the remaining structure of the flange 14 may provide first and second recess abutments 26, 27 extending along a plane E running through the longitudinal axis L of the camshaft segments 10 and 11. Both of the first adjustment device 20 and the second adjustment device 24 may be received in the flange 14 in a direction perpendicular to the surface of the cut-out abutment 26, 27. The first adjustment device 20 and the second adjustment device 24 may engage via their abutments 26, 27 for engaging in the corresponding recess 161, 181 of the second flange 15. Figure 6 schematically shows a tool 200 for adjusting the orientation of a first camshaft segment 10 relative to a second camshaft segment 11 in a first embodiment. The tool 200 may comprise a first camshaft segment 10 and a second camshaft segment 11 to be adjusted relative to the first camshaft segment 10 in an angle of rotation alpha. The tool 200 may comprise a first tool body 210 mounted to the first camshaft segment 10 which may comprise a first adjustment device 20 and a second adjustment device 24. The tool may further comprise a second tool body 220 mounted to the second camshaft segment 11. The second camshaft segment 11 may comprise a first abutment 26 and a second abutment 27, such that the first and second abutments 26, 27 can be brought into contact with the first and second adjustment devices 22, 24 respectively. And a second tool body 220 mounted to the second camshaft segment 11.

Thereby, the fine adjustment of the camshaft segments 10, 11 may be achieved after measuring the TDC position of all cylinder stations (not shown in Figure 6). The fine adjustment of the camshaft segments 10, 11 may be achieved via the tool 200. The tool 200 clamps the camshaft segments 10, 11 and further adjust the camshafts 10, 11 via screws in the function of first and second adjustment devices 20, 22. The tool 200, adjusted via screws, helps in compensating the tolerances between the camshaft segments 10, 11 and adjusts the intake closing time of a piston (not shown in Figure 6). The measuring can be performed without a cylinder head. As a result, the travel span of a piston could be measured at each cylinder station by a rotation of the crankshaft and the TDC position relative to a camshaft gear could be determined. Moreover, the position of the cam tip relative to a wheel could be measured with a pre-assembled camshaft.

Figure 7 schematically shows a tool 200 for adjusting the orientation of a first camshaft segment 10 relative to a second camshaft 11 and a second embodiment. The second embodiment of the tool 200 differs from the first embodiment in that the second tool body 220 is mounted to the second camshaft segment 11 via the same fastening means as the first tool body 210. The fastening means 28 run through the trough-holes which are discussed above in the context of Figures 1-2C, 4 and 5. In the present embodiment, the second tool body 220 may also be mounted to the second camshaft segment 11 where the fastening means running through the through-holes of the flanges 14, 15. Figure 8 schematically shows a flow diagram depicting a method according to an embodiment. The method disclosed in Figure 8 may be an adjustment method for adjusting the orientation of a first camshaft segment 10 relative to a further camshaft segment 11 coupled thereto in an angle of a shaft rotation a, comprising the steps of detecting S100 a target orientation displacement Da between the first camshaft segment 10 and the second camshaft segment 11, a step of calculating S120, based on the detected target orientation displacement Da, a target adjustment DF, at which the first and second adjustment devices 20, 24 need to be adjusted in order to reach the target orientation displacement Da between the first camshaft segment 10 and the second camshaft segment 11. The method may further comprise a step of adjusting S 140 the first and second adjustment devices 20, 24 such that the target orientation displacement Da between the first camshaft segment 10 and the second camshaft segment 11 is reached. The step of detecting SI 00 a target orientation displacement Da between the first camshaft segment 10 and the second camshaft segment 11 may further comprise a step of detecting an upper and lower dead center of the cylinder piston. Alternatively or additionally, the step of adjusting S140 may further comprise the steps of loosening one of the first and the second adjustment devices 20, 24 by the adjustment rotation DF and tightening the other one of the first and the second adjustment devices 20, 24 by the adjustment rotation DF such that the target orientation displacement Da between the first camshaft segment 10 and the second camshaft segment 11 is reached.

It will be obvious for a person skilled in the art that these embodiments and items only depict examples of a plurality of possibilities.

Hence, the embodiments shown here should not be understood to form a limitation of these features and configurations. Any possible combination and configuration of the described features can be chosen according to the scope of the invention. This is in particular the case with respect to the following optional features which may be combined with some or all embodiments, items and all features mentioned before in any technically feasible combination. As an example, a camshaft segment may have more than one cam mounted thereto in may have more than one flange. Each flange of a camshaft may have more than a first and a second flange recess and there may be more adjustment devices provided. Likewise, a camshaft may comprise more than a first and a second camshaft segment and a camshaft segment of a camshaft may be interlocked with more than one further camshaft segments. Also, instead of a second camshaft segment, a camshaft may also comprise a first camshaft segment and a non- camshaft segment with which the first camshaft segment is interlocked.

A camshaft segment for a camshaft of a gas engine may be provided, comprising a shaft having at least one cam mounted thereto. The camshaft may further comprise a flange comprising a first flange recess and a second flange recess in at least one adjustment device provided in one of the first and second flange recesses. The adjustment device may be configured such that it provides an adjustment abutment which may protrude longitudinally outwardly from the flange. The adjustment device may be configured such, that the adjustment abutment is adjustable in an angle of the shaft rotation. In other words, the camshaft segment may be adjusted by an adjustment abutment protruding longitudinally outwardly from the flange.

Thereby, the camshaft segment provides a simple, cost-effective and reliable camshaft segment which may be installed in a camshaft of a gas engine. In particular, the camshaft segment may be installed in a gas engine which is operated at a Miller cycle. Following this approach, each cam of a camshaft may be associated with a dedicated camshaft segment which may then be individually adjusted according to its orientation relative to the other cams of the camshaft. Thereby, the intake closing time in a Miller combustion process can be fine-tuned and geometric deviations due to tolerances in the camshaft may be compensated.

In a further development, the adjustment device may comprise a screw which is configured such that a screw head provides the adjustment abutment. Screws have the advantage, that their tooth step may serve as a gear ratio. To this end, small deviations may be adjusted more conveniently, as a turn of the screw head may translate to a much smaller change in the actual displacement of orientation. For example, turning the screw head at about 30° may translate to an orientation displacement of 0.1° about the shaft rotation angle of the camshaft segment. According to this development, the screws help in compensating the tolerances between the camshaft segment and in adjusting the orientation of the camshaft segment such that even small deviations may be compensated. In a further development, the flange may comprise an adjustment device, as a first adjustment device, provided in the first recess and a second adjustment device provided in the second recess. The first flange recess and the second flange recess may be provided opposite to each other on the flange. According to this embodiment, having two adjustment devices allows a convenient fixation of a camshaft segment orientation at various orientation displacements. Thereby, the adjustability of the camshaft segment may be improved.

In a further development, the first flange recess and/or the second flange recess may comprise a cutout of the flange configured such that the remaining structure of the flange provides a first and second cutout abutment extending along a plane running through the longitudinal axis of the camshaft segment. The first adjustment device may be received in the flange recess in a direction perpendicular to the cutout abutment. According to this embodiment, the first and/or the second adjustment devices may conveniently be integrated into the flange structure at only minimal impact on operation smoothness. Further, the first and second cut out abutments may both serve either as recipient for the adjustment device or as an abutment for an adjustment abutment of an adjustment device. Thereby, such a flange design may provide cut-out recesses without limiting the cut-out recesses to a particular function (receiving adjustment device or serving as an abutment).

In a further development, the flange may comprise a plurality of through-holes provided on a protruding circumference on the flange. According to this embodiment, the flange may be fast and to another flange or a further structure.

A camshaft may be provided comprising a first camshaft segment and a second camshaft segment and two adjustment devices, each providing an adjustment abutment, wherein each of the camshaft segment comprises a flange having a flange recess via which the flanges may be interlocked by means of first and second adjustment abutments of the first and second adjustment devices.

The solution proposes a fine adjustment of a camshaft segments after measuring the TDC position of all cylinder stations. The fine adjustment of the camshaft segments can be achieved via the adjustment device. The measuring can be performed without the cylinder head as a result, travel of piston could be measured at each cylinder station by a rotation of the crankshaft and the TDC position relative to the camshaft gear could be determined. Moreover, the position of the cam tip relative to the gear wheel could be measured with a pre assembled camshaft. In a further development, the first and second adjustment abutments may be adjustable in an angle of a shaft rotation, such that the first and second flanges may be adjusted angularly relative to each other. To this end, small deviations may be adjusted more conveniently, as a turn of the screw head may translate to a much smaller change in the actual displacement of orientation. For example, turning the screw head at about 30° may translate to an orientation displacement of 0.1° about the shaft rotation angle of the camshaft segment. According to this development, the screws help in compensating the tolerances between the camshaft segment and in adjusting the orientation of the camshaft segment such that even small deviations may be compensated.

In a further development, the first and second adjustment devices may be provided in the first and second flange recesses of the first flange of the first camshaft segment. Alternatively, the first adjustment device may be provided in a first flange recess of the first flange of the first camshaft segment and the second adjustment device may be provided in the second flange recess of the second flange of the second camshaft segment.

In general, two adjacent cut-out recesses (one of each flange) need to be interlocked via an adjustment device according to the present disclosure. To this end, a multitude of options is possible. According to one embodiment, one flange (either the first or the second) comprises both of the adjustment devices. Consequently, the cut-out recesses of the other flange in this embodiment then have the function of providing an abutment for the adjustment abutment of the adjustment devices.

According to another embodiment, each of the flanges comprises one adjustment device. Having all adjustment devices on one flange has the advantage of a simplified access of the adjustment devices. In order to adjust the adjustment devices, only one flange has to be considered.

In a further development, the first and second adjustment devices may each comprise a screw. A complementarity rotation of the screws by a screw angle of 30° may correspond to an orientation displacement between the first and second camshaft segments of 0.1°. Thereby, turning the screw head at about 30° may translate to an orientation displacement of 0.1° about the shaft rotation angle of the camshaft segment. According to this development, the screws help in compensating the tolerances between the camshaft segment and in adjusting the orientation of the camshaft segment such that even small deviations may be compensated.

In a further embodiment, each of the flanges may comprise a plurality of congruent through-holes provided on a protruding circumference of the flanges, each of the through-holes having a diameter greater than a diameter of a fastening rod running through said through hole. In each through hole, the difference in diameter between the through hole and the fastening Rod may provide a margin of 0.1. Thereby, the first and second camshaft segments may be fascinated via their first and second flanges by means of fastening rods while fine-tuning the relative orientation of the first camshaft segment relative to the second camshaft segment may still be achieved.

A gas engine may be provided comprising a camshaft segment and/or a camshaft according to the present disclosure. The gas engine may be configured to be operated at a Miller combustion cycle. Thereby, the camshaft segment provides a simple, cost-effective and reliable camshaft segment which may be installed in a camshaft of a gas engine. In particular, the camshaft segment may be installed in a gas engine which is operated at a Miller cycle. Following this approach, each cam of a camshaft may be associated with a dedicated camshaft segment which may then be individually adjusted according to its orientation relative to the other cams of the camshaft.

An adjustment method may be provided for adjusting the orientation of a first camshaft segment relative to a further camshaft segment coupled thereto in an angle of a shaft rotation. The method may comprise the steps of detecting a target orientation displacement between the first camshaft segment and the second camshaft segment, calculating, based on the detected target orientation displacement, a target adjustment, at which this first and second adjustment devices need to be adjusted in order to reach the target orientation displacement between the first camshaft segment and the second camshaft segment, and adjusting the first and second adjustment devices such that the target orientation displacement between the first camshaft segment and the second camshaft segment is reached.

Thereby, the camshaft segment provides a simple, cost-effective and reliable camshaft segment which may be installed in a camshaft of a gas engine. In particular, the camshaft segment may be installed in a gas engine which is operated at a Miller cycle. Following this approach, each cam of a camshaft may be associated with a dedicated camshaft segment which may then be individually adjusted according to its orientation relative to the other cams of the camshaft.

According to this embodiment, with the camshaft segment preassembled, a position of a cam tip relative to a cam shaft gear could be measured. Both measurements could be processed by a simple algorithm to determine the optimum position of each camshaft segment relative to the camshaft gear. Using a mechanism between camshaft segments like a screw (the adjustment device), fine adjustment of the camshaft segments could be performed. This compensates for the tolerances of production. An advantage of this method is also that the distance piston to cylinder head can be reduced.

In a further embodiment, the step of detecting a target orientation displacement between the first camshaft segment and the second camshaft segment may comprise a step of detecting an upper and lower dead center of the cylinder piston. As an example, the valve clearance at the cylinder head could be measured. This information could also be processed by the algorithm to take into account the minimum piston-valve distance. The dispersion of the compression ratio could be optimized at the same time. This can make the combustion of all stations easier to control, as smaller differences are expected. This would also mean higher efficiency and performance, as individual stations can determine the engine's parameters. According to a further development, the step of calculating may comprise calculating a target adjustment rotation angle at which screws of the adjustment devices need to be rotated in order to reach the target orientation displacement between the first camshaft segment and the second camshaft segment. To this end, small deviations may be adjusted more conveniently, as a turn of the screw head may translate to a much smaller change in the actual displacement of orientation. For example, turning the screw head at about 30° may translate to an orientation displacement of 0.1° about the shaft rotation angle of the camshaft segment. According to this development, the screws help in compensating the tolerances between the camshaft segment and in adjusting the orientation of the camshaft segment such that even small deviations may be compensated.

According to a further development, the step of adjusting may comprise the steps of loosening one of the first and the second adjustment devices the adjustment rotation and tightening the other one of the first and the second adjustment devices by the adjustment rotation angle such that the target orientation displacement between the first camshaft segment and the second camshaft segment is reached. Thereby, an easy-to-implement and failsafe adjustment method may be provided allowing a two-step validation of the adjusted position.

A tool may be provided for adjusting the orientation of the camshaft segment relative to a second camshaft segment in an angle of a shaft rotation. The tool may comprise a first tool body which is mounted to the first camshaft segment in which comprises a first and a second adjustment device and a second tool body mounted to the second camshaft segment comprising a first and a second abutment. The first and second tool body may be configured such that the first and second abutments can be brought into contact with the first and second adjustment device respectively. The solution proposes a fine adjustment of a camshaft segments after measuring the TDC position of all cylinder stations. The fine adjustment of the camshaft segments can be achieved via the tool. The tool clamps the camshaft segment and further adjust the camshafts via screws. The tool adjusted via screws, help in compensating the tolerances between the camshaft segments and adjusts the intake closing time. The measuring can be performed without the cylinder head as a result, travel of piston could be measured at each cylinder station by a rotation of the crankshaft and the TDC position relative to the camshaft gear could be determined. Moreover, the position of the cam tip relative to the gear wheel could be measured with a pre-assembled camshaft.

Accordingly, technical features each are described in connection with the above camshaft segment, camshaft, gas engine and tool may also relate and apply to the proposed adjustment method and vice versa.

Industrial Applicability With reference to the figures, a camshaft segment for a camshaft of a gas engine, a camshaft, and adjustment method and a tool for adjusting the orientation of two camshaft segments relative to each other are applicable in any suitable combustion engine, for example internal combustion engines ICE’s for gaseous fuels and in particular an ICE operating at a Miller combustion cycle. In practice, a camshaft segment for a camshaft of a gas engine, a camshaft and a tool for adjusting the orientation of two camshaft segments relative to each other and/or any combination of these various assemblies and components may be manufactured, bought, or sold to retrofit an engine, or an engine already in the field in an aftermarket context, or alternatively may be manufactured, bought, sold or otherwise obtained in an OEM (original equipment manufacturer) context.

As alluded to previously herein, the aforementioned embodiments may increase the improve the engine efficiency ratio as will be elaborated further herein momentarily. Referring to Figure 1, there is an embodiment shown disclosing a camshaft segment for a camshaft disclosing a laterally protruding adjustment device which may be adjusted in an angle of a shaft rotation. One skilled in the art will expected various embodiments of the present disclosure will have an improved simplicity, necessitating less maintenance and less complex adjustment technologies for camshaft segments.

The same advantages apply to the remaining figures, in particular to the camshaft comprising two camshaft segments, to the gas engine comprising the latter, to the adjustment method and to the tool for adjusting the camshaft segments relative to each other.

The present description is for illustrative purposes only and should not be construed to narrow the breadth of the present disclosure in any way.

Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” “include”, “includes”,

“including”, or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.

All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Certain steps of any method may be omitted, performed in an order that is different than what has been specifically mentioned or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications to certain aspects or features of various embodiments may be made to create further embodiments and features and aspects of various embodiments may be added to or substituted for other features or aspects of other embodiments in order to provide still further embodiments.

Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.