A method for monitoring the condition of oil in an engine is disclosed which includes the steps of determining a plurality of parameters, determining a fuel injection model, determining the area of the cylinder walls that is coated with soot, and responsively determining a soot model. The method may...http://www.google.com/patents/US5914890?utm_source=gb-gplus-sharePatent US5914890 - Method for determining the condition of engine oil based on soot modeling
