Longitudinally adjustable connecting rod with mass-optimized control slide

Patent metadata

Field	Value
Publication number	US-11525392-B2
Application number	US-201917283236-A
Country	US
Kind code	B2
Filing date	Oct 8, 2019
Priority date	Oct 8, 2018
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A longitudinally adjustable connecting rod with a hydraulic control device for effecting a change in the effective length of the connecting rod is provided. The hydraulic control device comprises a hydraulic control valve which comprises a hydraulically actuatable control slide that is preloaded by way of a control slide spring, and two outlet valves which can be actuated by the control slide by way of two control contours arranged at a distance from one another. The control slide comprises a low-pressure section with a low-pressure piston for hydraulically actuating the control slide. For optimizing the control slide for such a longitudinally adjustable connecting rod, the two control contours are arranged together in a high-pressure section of the control slide which is arranged on one side of the low-pressure section and separated therefrom by way of a sealing section disposed therebetween. The control contours each comprise a closure region with control cams and an opening region adjoining the control cams. The closure region has a smaller cross-section than the opening region. The mass of the section of the control slide disposed between the two closure regions corresponds at most to 0.95 times the envelope volume of this section multiplied by the density of steel (7.85 g/mm 3 ) due to the selection of material and/or the contouring narrowing in comparison with the opening regions. A respective control slide and a reciprocating piston engine are also provided.

First claim

The invention claimed is:

1. A longitudinally adjustable connecting rod with a hydraulic control device for effecting a change in an effective length of said connecting rod, wherein said hydraulic control device comprises a hydraulic control valve which comprises a hydraulically actuatable control slide that is preloaded by way of a control slide spring and two outlet valves which can be actuated by said control slide by way of two control contours arranged at a distance from one another, wherein said control slide comprises a low-pressure section (N A ) with a low-pressure piston for hydraulically actuating said control slide, wherein said two control contours are arranged together in a high-pressure section (H A ) of said control slide which is arranged on one side of said low-pressure section (N A ) and separated therefrom by way of a sealing section (D A ) disposed therebetween, that said control contours each comprise a closure region with control cams and an opening region adjoining said control cam, that said closure region has a smaller cross-section than said opening region, and that the mass of a portion of said control slide disposed between said two closure regions corresponds at most to 0.93 times the envelope volume of this portion multiplied by the density of steel (7.85 g/mm 3 ) due to the selection of material and/or the contourings narrowing in comparison with said opening regions.

2. The longitudinally adjustable connecting rod according to claim 1 , wherein the mass of the portion of said control slide disposed between said two closure regions corresponds at most to 0.85 times the envelope volume of this portion multiplied by the density of steel (7.85 g/mm 3 ) due to the selection of material and/or the contourings narrowing in comparison with said opening regions.

3. The longitudinally adjustable connecting rod according to claim 1 , wherein an axis (A S ) of said control slide is located in a plane which is substantially perpendicular to a crankshaft axis (A K ) operatively connected to said connecting rod and inclined relative to a longitudinal axis (A P ) of said connecting rod.

4. The longitudinally adjustable connecting rod according to claim 1 , wherein the section of said control slide disposed between said two closure regions contains both of said opening regions.

5. The longitudinally adjustable connecting rod according to claim 1 , wherein at least one support region is provided on the sides of said opening regions facing away from said closure regions and each of which is separated from the adjacent opening regions by way of a drain groove.

6. The longitudinally adjustable connecting rod according to claim 5 , wherein each of said opening regions is associated with its own support region and said two support regions are separated from one another by way of a narrowing groove.

7. The longitudinally adjustable connecting rod according to claim 6 , wherein a distance (A B ) from a center of said opening region to a center of said associated support region is in the range of 0.6 to 0.9 times the largest cross-sectional dimension of said opening region.

8. The longitudinally adjustable connecting rod according to claim 6 , wherein said support regions are arranged such that they are supported in any position of said control slide.

9. The longitudinally adjustable connecting rod according to claim 1 , wherein an opening stroke (H O ) provided by said control contours is at a ratio of 0.1 to 0.4 to a control stroke (H S ) of said control slide.

10. The longitudinally adjustable connecting rod according to claim 1 , wherein a control stroke (H S ) of said control slide is at a ratio of 0.1 to 0.3 to a center-to-center distance (M V ) of said two outlet valves.

11. The longitudinally adjustable connecting rod according to claim 1 , wherein said control slide is bored hollow in part from the end of said low-pressure section (N A ) and said bore extends into said sealing section (D A ).

12. The longitudinally adjustable connecting rod according to claim 1 , wherein said low-pressure section (N A ) at its outer end comprises said low-pressure piston, at its other end a stop flange, and a narrowing annular groove between said low-pressure piston and said stop flange.

13. The longitudinally adjustable connecting rod according to claim 1 , wherein at the outermost end of said high-pressure section (H A ), said closure region arranged there is configured as an extension such that a protection is created against a closing body of said outlet valve falling through.

14. A control slide for a longitudinally adjustable connecting rod according to claim 1 , wherein a low-pressure section (N A ) with a low-pressure piston for hydraulically actuating said control slide, where two control contours are arranged at a distance from one another together in a high-pressure section (H A ) of said control slide which is arranged on one side of said low-pressure section (N A ) and separated therefrom by way of a sealing section (D A ) disposed therebetween, where said control contours each comprise a closure region with control cams and an opening region adjoining said control cam, where said closure region has a smaller cross-section than said opening region and where the mass of the portion of said control slide disposed between said two closure regions corresponds at most to 0.95 times the envelope volume (H K ) of this portion multiplied by the density of steel (7.85 g/mm 3 ) due to the selection of material and/or the contourings narrowing in comparison with said opening regions.

15. A piston engine with at least one engine cylinder, a reciprocating piston moving in said engine cylinder, and at least one adjustable compression ratio in said engine cylinder, and as a longitudinally adjustable connecting rod connected to said reciprocating piston according to claim 1 .

16. The longitudinally adjustable connecting rod according to claim 9 , wherein said opening stroke (H O ) provided by said control contours is at a ratio of 0.2 to 0.3 to the control stroke (H S ) of said control slide.

17. The longitudinally adjustable connecting rod according to claim 10 , wherein said control stroke (H S ) of said control slide is at a ratio of 0.15 to 0.25 to the center-to-center distance (M V ) of said two outlet valves.

Assignees

• Iwis Motorsysteme Gmbh & Co Kg
• Avl List Gmbh

Inventors

• Heller Malte
• Bezner Stefanie
• Gallob Christian
• Rath Martin
• Kometter Bernhard

Classifications

• F16K31/524

  with a cam · CPC title

• F16K31/12

  actuated by fluid ({fluid-actuated lift valves F16K1/126} ; fluid-actuated check valves F16K15/00; fluid-actuated safety valves F16K17/00) · CPC title

• F02D15/02

  by alteration or displacement of piston stroke · CPC title

• F02B75/045 Primary

  by means of a variable connecting rod length · CPC title

• F16K31/44

  Mechanical actuating means · CPC title