Energy efficiency in hydraulic systems

Abstract

The present invention describes use of a fluid having a VI of at least 130 to improve the energy efficiency of a hydraulic system. Furthermore, the present invention relates to a hydraulic system comprising a hydraulic fluid having a VI of at least 130, a unit for creating mechanical power, a unit that converts mechanical power into hydraulic energy, and a unit that converts hydraulic energy into mechanical work. Preferentially, engine speed can be reduced to decrease load and stress while delivering the same amount of hydraulic power.

Description

Claims

1. A use of a fluid having a VI of at least 130 to improve the energy efficiency of a hydraulic system.

2. The use according to claim 1, wherein the energy consumption is lowered at least 5%.

3. The use according to claim 1, wherein the system performance of the hydraulic system is improved.

4. The use according to claim 3, wherein the system performance is improved at least 5%.

5. The use according to claim 1, wherein the life time of a unit providing mechanical power to the hydraulic system is improved.

6. The use according to claim 5, wherein the engine speed is reduced to decrease load and stress while delivering the same amount of hydraulic power.

7. The use according to claim 1, wherein the fluid has a VI of at least 150.

8. The use according to claim 7, wherein the fluid has a VI of at least 180.

9. The use according to claim 1, wherein the fluid is a NFPA double viscosity grade, triple viscosity grade, quadra viscosity grade, or penta viscosity grade hydraulic fluid.

10. The use according to claim 1, wherein the fluid is obtained by mixing a base fluid and a polymeric viscosity index improver.

11. The use according to claim 10, wherein the base fluid has a kinematic viscosity at 40° C. according to ASTM D 445 of 35 mm2/s or less.

12. The use according to claim 11, wherein the fluid comprises at least 60% by weight of at least one base fluid having a kinematic viscosity at 40° C. according to ASTM D 445 of 35 mm2/s or less.

13. The use according to claim 11, wherein the base fluid has a viscosity index of 120 or less.

14. The use according to claim 13, wherein the fluid comprises at least 60% by weight of at least one base fluid having a viscosity index of 120 or less.

15. The use according to claim 1, wherein the fluid comprises a mineral oil and/or a synthetic oil.

16. The use according to claim 15, wherein the fluid comprises a API group I, API group II, API group III oil, a API group IV or API group V oil.

17. The use according to claim 1, wherein the fluid comprises a polyalphaolefin (PAO), a carboxylic ester, a vegetable ester, a phosphate ester and/or a polyalkylene glycol (PAG).

18. The use according to claim 1, wherein the fluid comprises at least one polymer.

19. The use according to claim 16, wherein the polymer comprises units derived from monomers selected from acrylate monomers, methacrylate monomers, fumarate monomers and/or maleate monomers.

20. The use according to claim 19, wherein the fluid comprises a polyalkylmethacrylate polymer.

21. The use according to claim 18, wherein the fluid comprises a polymer obtainable by polymerizing a mixture of olefinically unsaturated monomers, which consists of a) 0-100 wt % based on the total weight of the ethylenically unsaturated monomers of one or more ethylenically unsaturated ester compounds of formula (I)

22. The use according to claim 18, wherein the polymer is obtained by a polymerisation in a API group II or group III mineral oil.

23. The use according to claim 18, wherein the polymer is obtained by a polymerisation in a polyalphaolefin (PAO).

24. The use according to claim 23, wherein the PAO has a molecular weight in the range of 200 to 10000 g/mol.

25. The use according to claim 18, wherein the at least one polymer is obtained by polymerizing a mixture comprising dispersant monomers.

26. The use according to claim 18, wherein the at least one polymer is obtained by polymerizing a mixture comprising vinyl monomers containing aromatic groups.

27. The use according to claim 18, wherein the at least one polymer has a molecular weight in the range of 10000 to 200000 g/mol, specifically 25000 g/mol to 100000 g/mol.

28. The use according to claim 18, wherein the fluid comprises 0.5 to 40% by weight of the at least one polymer.

29. The use according to claim 28, wherein the fluid comprises 10 to 30% by weight of the at least one polymer.

30. The use according to claim 18, wherein the fluid comprises at least two polymers having a different monomer composition.

31. The use according to claim 30, wherein at least one of the polymers is a polyolefin.

32. The use according to claim 31, wherein at least one of the polymers comprises units derived from alkyl ester monomers.

33. The use according to claim 32, wherein the weight ratio of the polyolefin and the polymer comprises units derived from alkyl ester monomers is in the range of 1:10 to 10:1.

34. The use according to claim 1, wherein the fluid comprises an oxygen containing compound selected from the group of carboxylic acid esters, polyether polyols and/or organophosphorus compounds.

35. The use according to claim 34, wherein the oxygen containing compound is a carboxylic ester comprising at least two ester groups.

36. The use according to claim 35, wherein the oxygen containing compound is a diester of carboxylic acids comprising 4 to 12 carbon atoms.

37. The use according to claim 36, wherein the oxygen containing compound is an ester of a polyol.

38. The use according to claim 1, wherein the fluid has an ISO viscosity grade in the range of 15 to 150.

39. The use according to claim 1, wherein the fluid is used at a temperature in the range of −40° C. to 120° C.

40. The use according to claim 1, wherein the fluid comprises antioxidants, antiwear agents, corrosion inhibitors and/or defoamers.

41. The use according to claim 1, wherein the fluid is used in military hydraulic systems, in hydraulic launch assist systems, in industrial, marine, mining and/or mobile equipment hydraulic systems.

42. The use according to claim 1, wherein the hydraulic system comprises at least one unit providing mechanical energy, at least one unit that converts mechanical energy into hydraulic energy, at least one pipe for transmitting fluid under pressure and at least a unit that converts the hydraulic energy of the fluid into mechanical work.

43. The use according to claim 42, wherein the unit providing mechanical energy comprises a combustion engine.

44. The use according to claim 42, wherein the speed or power output of the unit can be controlled and adjusted.

45. A hydraulic system comprising a hydraulic fluid having a VI of at least 130, a unit for creating mechanical power, a unit that converts mechanical power into hydraulic energy, and a unit that converts hydraulic energy into mechanical work.

46. The hydraulic system according to claim 45, wherein the engine speed can be reduced to decrease load and stress while delivering the same amount of hydraulic power.

47. The hydraulic system according to claim 45, wherein the mechanical power output of the engine or electrical motor can be operated at less than 98% of its full power capacity to deliver the same amount of hydraulic power as the hydraulic system utilizing an HM grade fluid with a viscosity index less than 120.