Review on Effect of Machine oils on the Efficiency of Operating Thermal Machines


  • Nagham Mahmood Aljamali
  • Widad Hashim Yahya Almuhana
  • Hanan Ali Hussein


Machine, Oil of motors, Viscosity, Thermal


It is known that there is an effect of engine

oils on the efficiency of operating thermal

machines, as engine oil is the mainstay in

measuring the efficiency of the machine and is

used to lubricate internal combustion engines.

Its primary purpose is to lubricate the moving

parts. The viscosity index is one of the

important factors for the quality of

machinery and engine oils, which is the rate

of change in the viscosity of the fluid between

two temperatures. The lower the number, the

lower the viscosity the more the oil heats up.

The higher the number, the lower the

viscosity decreases as the oil heats up, Some

synthetic oils have sufficient viscosity stability

(index) to qualify as multi-grade oils. But for

mineral-based oils, it has another story. It is

configured for low temperature properties.

Then viscosity index improvers are added to

  1. These additives improve the thinning of the

oils with increased heat. This allows oils with

a lower viscosity to also meet the

requirements of higher temperatures. Oils

with multiple viscosity levels provide the low

temperature fluidity and high-temperature

stability required to operate in changing

weather conditions.