Online oil dilution measurement


As a result of the "Renewable energy" Energy Directive 2009/28/EC, EU member states are obliged to increase the proportion of renewable energy in total energy consumption to an average of 20% by 2020. This has a direct impact on the development of internal combustion engines.

The dilution of engine oil by fuels containing ethanol, such as Super E10, or by diesel fuels containing biodiesel, can significantly alter the lubricating properties and cause damage to the engine. Since ethanol has a higher vaporization enthalpy and lower vapor pressure, fuels containing higher levels of ethanol tend to produce unfavorable mixtures during cold starting and engine warm-up compared to conventional gasoline. There is an increased likelihood of gasoline entering the oil under these engine conditions. For diesel engines, the post-injection conditions that trigger DPF (diesel particulate filter) regeneration are of particular interest. Although the chemical and physical properties of biodiesel and diesel components are similar, biodiesel fuels tend to dilute the engine oil more during DPF regeneration.

Other aspects of today's internal combustion engine development, such as the use of new combustion methods and catalyst heating, likewise facilitate oil dilution - even when using regular gasoline. Identifying strategies to counteract or optimize engine oil dilution requires a fundamental understanding of the mechanisms of fuel entry and exit into the engine oil. Measurement equipment is, therefore, necessary to determine the percentage of fuel in engine oil and preferably provide real-time results.


The V&F Online Oil Dilution Measurement System, consisting of V&FFuelSense and V&F LubeSampler, provides automotive technicians with the means to continuously measure oil dilution. The LubeSampler consists of a separate oil circuit connected to the engine's oil sump. A circulating pump ensures that the oil is well-mixed. A small sample is drawn with a metering pump set at 1.0ml/min. A metering valve introduces the sample, along with a carrier gas, into the thermal desorber, where the oil is separated from its characteristic volatile components, resulting from the dilution of the oil by fuels These volatile components depend on which fuel is used. They are ethanol in the case of fuels containing ethanol, benzene, toluene, and xylene in the case of gasoline, or hydrocarbons such as C4H10 in the case of diesel B7.

The V&FFuelSense with the patented IMR technology (Ion Molecule Reaction) can identify all these components down to a low ppb level to achieve detection limits of oil dilution below 0.2% fuel in oil. To calibrate the system, mixtures with known levels of fuel in oil are prepared, and thermal desorption is used to quantify the signals from the marker components such as ethanol. Thus, signals from the sample can be correlated with unknown concentrations of fuel in oil.

Photo Industry Solution V&F Automotive Online Oil Dilution Measurement


Unlike conventional off-line methods, the V&FFuelSense and V&F LubeSampler provide real-time results. Time profiles of oil dilution mechanisms for stationary and dynamic engine test cycles are generated, enabling technicians to develop strategies to minimize engine oil dilution by fuels.

The V&F FuelSensemass spectrometer with its IMR technology, unlike the FID determination of a signal from a sum of hydrocarbons, can selectively determine the components that desorb from the oil. This allows in-depth studies of not only the time profiles, but also the chemistry associated with the oil dilution process.


  • Suitable for diesel and gasoline engines
  • Fast measurements within minutes
  • Detection level below 0.2 % dilution
  • Continuous oil sampling with recirculation to the oil sump
  • Time saving, easy installation and operation
  • Minimized service and operation costs