Filtern
Dokumenttyp
Sprache
- Englisch (2)
Referierte Publikation
- nein (2)
Schlagworte
- EAL (2) (entfernen)
The use of alternative base oils, like esters or polyglycols, with more intrinsic properties for the lubrication of automobile engines has a potential for ecological and technical advantages. Being in competition with hydrocarbon-based formulations, detailed knowledge of several thermophysical and viscometric properties as well as tribological properties over a large temperature range are required (mapping). The tested polymer-free polyglycols and ester-based formulations displayed no visible tribological weaknesses regarding wear resistance and EP-behavior as well as offering significant advantages in order to meet metal- and ash-free and bio-no-tox criteria. Especially the formulated polyglycols without friction modifiers also showed an intrinsic retention of low coefficients of friction and a hydrodynamic film forming behavior comparable to hydrocarbon-based factory-fill oils. The wear resistance and EP-behavior of low-additivated polyglycols, but also of esters, can be enhanced by means of triboactive materials. Lubricious oxides or triboactive materials and polar base oils, or a combination thereof, may substitute the EP and AW properties realized by the additives, thus enabling long drains and responding to eco-tox or bio-no-tox requirements as well as restrictions from the chemical box.
The use of alternative oils for the lubrication of automobile engines has a potential of ecological and technical advantages. It requires the detailed knowledge of several thermophysical and viscometric properties in a large temperature range (mapping). Therefore, the following properties of up to twenty-eight different oils have been measured in the temperature range from 22 °C to 150 °C: density, heat capacity, thermal conductivity, viscosity at ambient pressure, viscosity under shear rates above 10 6 s-1, and the viscosity at elevated pressures (maximum 100 MPa). The last two have been measured with a substantially improved and a newly developed apparatus, respectively. The pressure- viscosity coefficient has been measured on four hydrocarbon-based, factory-fill oils, a paraffin oil and twenty-three alternative oils. Nine of the alternative oils are based partly or completely on esters, the other fourteen on polyglycols, two of them additionally on water.