Engine Oil Consumption Measurement

Background

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Engine oil loss is a severe problem in today’s engine development. Downsizing engines together with turbocharging and (or) reducing piston ring thickness in combination with increased cylinder pressures result in engine oil loss. Engine oil carries about 2000 – 3000 ppm sulfur that is oxidized in the flame to produce SO2. This may lead to reduced catalyst activity.

Furthermore, other oil byproducts like phosphorus affect sensor characteristics which in turn results in incorrect engine management and catalyst operation. Minimizing oil loss requires knowledge of the engine states in which it occurs. Gravimetric methods can provide some information about steady state operation but for transient engine operation real-time measurement methods are obligatory in order to obtain time resolved oil consumption profiles.

Solution

SO2 is a tracer for oil loss when it is measured in the raw exhaust gas. With known concentrations of sulfur in fuel and oil the oil consumption rate in g/h (grams per hour) can be calculated from the concentration of SO2 in the exhaust gas. The V&F GasOxidizer is used to convert all other possible sulfur compounds including sulfur bound to particulates into pure SO2.

The sensitive V&F mas spectrometers with its IMR-MS technology can detect SO2 concentrations as low as  40 ppb . Typically, modern engines consume 2 to 3 grams of oil per hour which produces SO2 signals from 0.2 to 0.7 ppm SO2 in the raw exhaust gas when high sulfur oils (> 5000 ppm S) are used.

Advantage

The SO2 tracer method with the V&F mass spectrometers yields real time data and thus enables the engineer to create detailed oil consumption profiles whereas offline methods such as gravimetry usually only provide two data points, before and after the test. In addition, they are time consuming and bear several sources of error.

In contrast to radioactive tracer methods, the setup and handling of our gas analyzers is completely safe with regards to working safety. The V&F GasOxidizer facilitates conversion of all sulfur present in the exhaust gas stream either as gaseous compounds or as particulates. Oil consumption monitoring is hence possible in Gasoline, CNG and Diesel engines. Once the installation is complete the desired number of test cycles can be run without a need for access to the engine test cell or the instrument.

Highlights

  • Real time oil consumption measurement
  • Time saving – easy installation
  • For diesel, gasoline and CNG engines

Reference customers (excerpt)

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Applicable instruments

LubeSense
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GasOxidizer