Two models are available: the Q3000 which measures viscosity over the range 10-350 cSt and the Q3050 viscometer with a range of 1-700 cSt (fig.3). The SpectroVisc Q3000 Series viscometer design includes an upper sample-loading well, microchannel, and temperature control electronics to measure fluids at a constant temperature of 40☌. SpectroVisc Q3000 Series Viscometer Theory and Design (On track analysis) 2 Change of Kinematic Viscosity of different kinds of oil depending of % fuel dilutionġ. SpectroVisc Q3000 Series Viscometer analyzed in the next chapter is able to capture dilutions up to 15%.įig. Instead, when fuel dilution is between 7 and 10 %, kinematic viscosity value is 30 - 40 mm2/s lower and that makes oil engine unusable for its purpose. 2 and in particular to synthetic oil, that is the type used in racing contests, we can notice that until the percentage of fuel is less than 5%, kinematic viscosity decreases of little more of 20 mm2/s, which is a tolerable change. ![]() According to the state of the art, oil films should be stable up to 10 wt% of fuel dilution but ultimately relevant published data for fuel-engine oil mixture demonstrate that where the amount of fuel in oil is up to 4 or 5 % it could be still adequate for use in engines, while amounts of 7 to 10 % of fuel in oils are considered unacceptable levels (taking into account flash point and fire point, too). 1), but never as much as the value of petrol in oil decreases this mixing condition. It is true that shear stresses and high temperatures can quickly worsen lubricant "sustenance" conditions (Fig. If it’s high, viscosity will be greatly reduced according to Kendall - Monroe relation: It is evident that in a racing engine these two factors are decisive, but they are both buffered with the early replacement of the oil charge.įuel dilution is a very important factor in competitions, and it also gives us a double signal. Indeed, these are the fundamental factors that influence the life of an oil. ![]() ![]() The viscosity decrease depends on the shear stresses and on the mixing with the petrol. The state of health of the oil on one side and the other the state of health of the engine. Viscosity is one of those few values that give us a double information. The entire first part of this work focused on making it clear how important it is to use low viscosity lubricating oils in competitions and how much this parameter influences the power that actually transfers between the crankshaft and the rear wheel / wheels. Although elementary analysis may be important, oils are not classified for the level of additives or the origin of bases, but rather for viscosity tables that are consulted according to the user. The signal we want to capture in this chapter is viscosity, the most important parameter in terms of classification of lubricants. Analysis of the oil is a concept that must necessarily be accompanied by the amplification of a signal that must carry with it objective information, the only ones useful for the diagnostic phase. It is also evident, however, that the famous weak signals (about which we discussed in the previous articles) which are decisive in the analysis of the oil can not be captured by the sensitivity of the human body. Viscosity and smell have always been the two parameters measured in a natural way by man, that is touching and sniffing. It is evident that the intellectual passage between a purely qualitative determination and objective determinations has been slow and progressive. Indeed, before the arrival of extremely technological (and compact) instruments the first way that the mechanics of the racing teams had, was to pass the lubricating oil between thumb and forefinger. It is the only one that allows to understand through a single analysis, if the engine is "good" or "bad" compared to a consolidated trend on the test bench, or based on past experience.īut interesting values, as well as in industry even in competitions, are not only those one given by elementary analysis. ![]() If we face a weekend on the circuit, it is clear that Spectroil is the main instrument to know the health of the engine.
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