The Use of the Portable Field Falling Needle Viscometer to Determine Engine Oil Contamination by Diesel Fuel under In-Service or Field Conditions

Abstract

A simple and accurate way of avoiding costly engine damage due to diesel fuel contamination is a necessity for owners and operators of heavy-duty diesel engines or industrial engines, or both. Dynamic viscosity changes are most sensitive to changes in liquid composition. Among other applications, this phenomenon has been used to detect composition changes in anti/deicing fluids for preventing the icing of airplane surfaces in cold or snowy-weather environments, or both. It can also determine the extent of contamination of one liquid by another such as oil contamination by fuel for the diesel engines of heavy equipment or industrial engines. Although increased engine protection and extended lifetime can be achieved with viscosity measurement of engine oil, inexpensive and accurate field measurements with a small sample amount have been proven to be difficult. Current practice requires samples to be sent to the laboratory with added reporting time and analysis cost. This report assesses the accuracy and usability of a portable technique to determine viscosity changes of engine oil by diesel contamination in internal combustion engines under in-service or field conditions. The field viscosity measurements were made using the portable field falling needle viscometer (FNV) while changing both the diesel concentration from 2% to 10% and the temperature from 15 to 40 °C. Because of the simplicity of the FNV principle, automatic or manual portable field FNV (PFV) is made available for lubricants and greases even under in-service or field conditions without any instrument calibration by using the constant gravity. The viscosity measurements with an automatic and inexpensive manual portable field FNV (PFV) are better than 0.75% and 1.29% accuracy, respectively. These portable field viscosity measurements not only extend the engine life and usage time of diesel engine oils but also allow for further elucidation of diesel contamination to engine oils.