Thread: DIY Oil Condition Tester View Single Post
 01-29-2016, 08:25 PM #14 (permalink) gone-ot ...beats walking...   Join Date: Jul 2009 Location: . Posts: 6,190 Thanks: 179 Thanked 1,522 Times in 1,123 Posts The SAE papers that I read about the original GM Oil Life Monitor (OLM) system stated that it only used TIME and TEMPERATURES, there were NO special sensors (viscosity, ph, etc.) involved. How the OLM works. GM engineer, Ms. Ellen Shirley Schwartz, PhD, is one of the researchers who developed the GM patent (#6,327,900 B1, dated 11-Dec-2001): http://www.google.com/patents?id=jpo...page&q&f=false ...the flow chart in Fig. 2 explains which parameters the OLM monitors and measures. Basically, there are three controlling parameters: the engine revolutions, the oil temperature, and the oil contamination: • the oil "temperature (T) equation" used in the program is: T(o) = k(2) + k(3)*S(e) + k(4)*T(c) + k(5)*F(q) - k(6)*T(a) ± k(7)*V(s) ...where: S(e) = engine rotational speed, rpm T(c) = coolant temperature, șC F(q) = fuel quantity, cubic-millimeters-per-cylinder T(a) = air intake temperature, șC V(s) = vehicle speed, mph k(2) = constant (-9.0 *) k(3) = constant (0.012 *) k(4) = constant (0.95 *) k(5) = constant (0.21 *) k(6) = constant (0.001 *) k(7) = constant (0.01 *) • the oil "contamination (C) equation" used in the program is: C = k(8) + k(9)*I(t) + k(10)*F(q) + k(11)*T(o) + k(12)*S(e) ...where: I(t) = fuel injection timing, degrees crank angle F(q) = fuel injection quantity, cubic-millimeters-per-cylinder T(o) = calculated oil temperature, șC S(e) = engine rotational speed, rpm k(8) = constant (-2.7 *) k(9) = constant (0.2 *) k(10) = constant (0.03 *) k(11) = constant (0.02 *) k(12) = constant (0.001 *) * = derived values for GM 6.6L V8 diesel test engine. Thus, contrary to what Mr. Bob-the-Oil-Guy said, GM is actually tracking "calculated" oil contamination--not its ZDDP content--with the OLM...at least, as stated in their 2001 US Patent. Last edited by gone-ot; 01-29-2016 at 10:22 PM..
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