Archive: Institute of Measurement Technology
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Evaporation of lubricating oil in a combustion chamber of gasoline engines
With reference to oil consumption the piston ring package is an open system because of the indispensable wetting of the cylinder wall with lubricating oil. The process of combustion and the charge exchange process causes rateable evaporating of lubricating oil from the cylinder wall. The evaporated lubricating oil together with other partial quantities of consumed lubricating oil is transported to the exhaust system during the charge exchange process and so it becomes a loss to the oil circulation of the engine.
The priority of this research project is to verify the simulation program PRO which was designed in the FVV-project 646. The result of this program is the consumed oil amount due to the 3 main effects, including evaporated oil from the cylinder-liner and oil which is transported with blow-by and reverse-blow-by gas streams. The result is given out for each crank angle of a work cycle.
For the first time verification is possible by a rapid emission measurement method which quantifies the vaporous parts of the oil in the cylinder charge. For this the gas will be taken out of the cylinder and online analyzed in a mass spectrometer. The thermodynamic change of state of the cylinder charge and its composition including the charge exchange process is described by working cycle calculation.
The crucial task of this research project is the final correlation of the measurement results with the results of the simulation calculation. Therefore measurements of the miscellaneous parameter variations at the test bed are done while the simulation is performed at the same time. The aim of this approach is to ensure an adequate correlation between measurement and calculation by means of optimization of the physical models in the simulation.
Project Executing Organisation: Forschungsvereinigung Verbrennungskraftmaschinen (FVV) e.V.
Term: Oct. 2004 - Sep. 2007
Setup at the engine test bench: A Triple-Quad-Mass-spectrometer Lubrisense 1200, B Intake System, C Engine, D Probe tip of sampling device at cylinder 1, E Connections of fast data acquisition.
RF-Only-Operation with resulting high-pass mass filter
Transient effect on oil emission at revolving piston rings measured in the combustion chamber, which is traced back to Reverse-Blow-by.
Shown is the characteristic diagram of oil emission of the examined gasoline engine. In the headline the crankshaft angle is indicated, which increases over all four strokes of a working cyle from 0° to 720°. It is clearly visible, that the amount of evaporated oil is at its maximum at two points in time: at ignition (after 360°) and at emission (at 540°).
