Patent ID: 6776024
Filing Date: 2004-08-17
Classification: F01M,G01N

Abstract:
A method of evaluating wear in engine oil based on viscosity measurements, accounting for an addition of fresh oil to aged engine oil using an oil viscosity sensor, an oil level sensor and a connected electronic analyzer having a display device, and determining an aging of the aged engine oil and determining an oil change interval recommendation resulting therefrom as a reference value by evaluating a change in a prevailing oil viscosity at at least one temperature, in comparison with a viscosity of the fresh oil added at a last oil change, the method comprising:detecting a quantity of oil used in the addition of the fresh oil using the oil level sensor; determining a viscosity of an oil mixture of the aged engine oil and the fresh oil together with a temperature using the oil viscosity sensor at at least one temperature; determining the quantity of the fresh oil added, using the electronic analyzer, from a difference between one of an old oil level and oil volume, and one of a new oil level and oil volume; determining a viscosity of the fresh oil from a viscosity of the aged engine oil immediately before and immediately after the addition of the fresh oil; and calculating a hypothetical initial viscosity as a new corrected reference value from an initial viscosity of the aged engine oil when new, the oil volume still present at a point in time of the addition, a determined viscosity of the fresh oil, and a determined quantity of fresh oil.