The Oilyzer product uses the same physics for sensing the TBN of oil as many of the oil sensors used by automotive manufacturers. Although GM uses predictive statistics to assess the next oil change (often surpassing 15K mile oil replacements for newer vehicles), other manufacturers use capacitive sensing for detecting the oil acidity level, typically based on the TBN (Total Base Number)of the oil under test. As oil becomes more acidic due to friction, temperature, pressure, suspended contaminants etc, the TBN value changes, and is a very reliable indicator of oil quality. Optical or Photoelectric sensing has been used in the past to gauge the viscosity and opacity of oil, but has been proven to be unreliable and is not a technology used in the "Oilyzer" product. The combined capacitive and resistive aspects of measuring oil health or quality determines acidity, viscosity and contaminants (metal particulates, soot, dirt, coolant, water) with the exception of gasoline.
The Oilyzer is able to capture most of the information regarding the "TBN" of oil when compared to a high end spectroscopy, flash and chemical based tests. It is a scientific and technologically reliable indicator when measured against subjective human based test methods (based on the color of oil or driving mileages.
There is a plethora of scientific information on the web and in scientific journals or on SAE.org supporting the premise for reducing the number of unnecessary oil changes (replacements) and to extend driving distances based on TBN and other factors related to scientific measurement rather than by subjective means.
http://www.calrecycle.ca.gov/UsedOil/OilChange/
http://www.nordicgroup.us/oil.htm
http://money.blogs.time.com/2009/09/08/the-3000-mile-oil-change-myth/
www.sae.org keywords engine "oil dielectric longevity"
The Oilyzer tests oil the same way a person is able to determine their health by a blood test. It targets the four main variables for general oil testing;
1. Total mileage of the engine.
2. User driving habits (stop start versus long haul driving).
3. Environment the vehicle is typically driven (ambient temps, humidity, etc).
4. Engine condition (poor, fair, good).
Auto manufacturers already have many vehicles on US roads today,with oil sensors on board, surpassing 15K miles between oil changes without any oil or engine modifications warranting such mileage extensions (see GM technical forum). The 3000 mile myth stems from the post WWII era, and it is easy to understand that oil and engine science and technology has advanced to accommodate superior performance and longevity of oil and an owner's vehicle since that era.