HOW DO VOLATILITY, VISCOSITY AND V.I. IMPROVERS AFFECT OIL CONSUMPTION?

Experimental oils were compounded in such a manner that the effect of volatility and viscosity on consumption could be studied independently. Close cut fractions between 40 and 170 S.U.S. at 100 deg F showed differing volatility characteristics in laboratory engine tests as measured by consumption rate, viscosity increase, and vacuum distillation. Consumption properties were also studied for oils with constant volatility, but varying in viscosity from 2 cs to 6 cs at 350 deg F. Laboratory and road tests of viscosity index improved motor oils indicated that their consumption characteristics varied in relation to oils with no viscosity index improver.