Stručni rad
IMPACT OF FRESH AND SHEARED OIL VISCOSITY REQUIREMENTS ON THE FORMULATION OF HYDRAULIC FLUIDS
Christian D. Neveu
; Evonik RohMax Additives, Germany
Michael J. Alibert
; Evonik RohMax Additives, Germany
Franco Camera
; Evonik RohMax Additives, Germany
Sažetak
For many years hydraulic oils were selected using the ISO 3448 viscosity classification. Developed in the mid-seventies, it defines a finite number of discontinuous grades based on a minimum and maximum viscosity at 40 °C. In 1997, efforts by ASTM resulted in the ASTM D 6080-97 classification that included several viscosity requirements on the fresh and sheared oil. More recently, two new sets of viscosity and VI limits on the fresh and sheared oil were proposed to provide improved equipment efficiency compared to conventional HM oils. These are the Maximum Efficiency Hydraulic Fluid definition (MEHF) and the National Fluid Power Association (NFPA) guidelines for hydraulic fluid viscosity selection.
Any additional viscometric requirement to the ISO grade definition introduces new constraints on both the kinematic viscosity and VI of the formulation. Using a large number of blends based on VI Improvers having a different shear stability level, we investigated the impact of the viscosity constraints included in the MEHF and NFPA guidelines on the formulation windows of the three most common ISO grades. The degree to which the guidelines overlap, the so-called “formulation window” was found to depend on the ISO grade and shear stability of the VI Improver considered. This work provides a framework for an improved ability to select formulation targets considering these new guidelines.
Ključne riječi
maximum efficiency hydraulic fluid MEHF; energy efficiency; hydraulic transmisions; viscosity; shear stabilty
Hrčak ID:
55560
URI
Datum izdavanja:
30.6.2010.
Posjeta: 2.194 *