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On 2008, Jun 17, , at 07:29, Santos Ramirez <ramirez@physics.tamu.edu>
wrote:
Read this in the yahoo news, concerning the myth of
changing the oil in a vehicle every 3,000 miles.
Idea for new experiment in the physics labs
or something already being done?
SR
*******************************************
Because of the many external conditions and parameters that have to be
taken into account, calculating the precise maximum service interval
using
mathematical models alone is difficult. Now, Daimler AG has developed a
more direct and precise way to monitor oil quality directly on board a
vehicle.
Daimler uses a special sensor integrated into the oil circuit to monitor
engine oil directly. Oil doesn’t wear out, but rather dirt and impurities
cause oil to lose its ability to lubricate properly, dictating the need
for a change. Daimler uses the oil’s “permittivity,” that is, the ability
to polarize in response to the electric field. If the engine oil is
contaminated by water or soot particles, it polarizes to a greater extent
and its permittivity increases.
To evaluate the quality of the oil, permittivity is measured by applying
an AC potential between the interior and exterior pipes of an oil-filled
sensor to determine how well the oil transmits the applied electric
field.
http://autos.yahoo.com/articles/autos_content_landing_pages/586/the-3000-mile-oil-change-myth/;_ylc=X3oDMTE0cnVqb3Q4BF9TAzI3MTYxNDkEc2VjA2ZwLXRvZGF5BHNsawMzMDAwLW9pbA--
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