Research

Oil transport in the oil control ring

In order to be able to design the piston assembly of a combustion engine, knowledge of oil transport in the piston ring is necessary. As the availability of this knowledge is poor, a one-cylinder research engine with complex measuring technology was developed in the project for investigating the tribologic states of the piston assembly. Among others, this measurement technology comprised a measurement lever system integrated into the crankcase as well as processes for determining lubricant viscosity and piston ring rotation. A newly developed simulation model reflected the piston ring package and determined the influencing factors on the oil supply. In this way the blowby (the gas that blows past the piston rings during the compression stroke), the axial ring movement, and the intermediate ring pressure for example can be reliably projected. As the developed flow solver for determining the oil transport is designed for industrial use, users can directly benefit from the project results.

» With the test engine physical relations for the oil transport around the piston ring are explored that can be implemented into mathematical models. In addition, the resulting simulation tool could be validated using the measurements gained from the engine. This knowledge is of enormous value for the targeted design of series-produced engines as it contributes to combustion engine emissions being reduced to the absolute minimum. «
Dr. Arnim Robota (Federal Mogul Burscheid GmbH)

Motivation

The piston assembly is a central element of a combustion engine. When being designed proper dimensioning plays an important role for ensuring the necessary oil supply. The objective of the project was to develop a test engine and measurement technology to research the influencing factors on the oil supply as well as the effect mechanism of the piston ring pack. In addition the calculation model for the oil supply to the piston group should be improved and a Computational Fluid Dynamics (CFD) simulation model of the piston ring pack should be developed.

Methodology

The starting point of the project was the construction of the test engine. The focus of the work was on developing measurement technologies such as the measurement lever system in the crankcase. To determine the lubricant viscosity an optical technology based on the principle of laser-induced fluorescence was used. The determining of the piston ring rotation was done using two radioactive samples on which the circumferential position of the piston ring thrust was collected. On the basis of commercially available software, the project partner developed simulation models of the one-cylinder test engine. For simulating the oil transport, a flow solver was used which can show both the multiphase flows (oil/gas) as well as the movement of the piston ring.

Result

Using the FVV test engine it is possible to research the influencing factors on the oil supply and to establish the effect mechanisms of the piston ring pack. The lubricating film thickness measurement is able to deliver exact measurements about the state of the lubricating film in the piston ring assembly. The evaluation of the piston ring rotation measurement makes it possible to calculate the angular position of the ring thrust during engine operation in real time. The effectiveness of the simulations was tested and validated on two different piston ring geometries. The measured and calculated values for the blowby, the axial ring movement, and the intermediate ring pressure matched very well. The newly developed flow solver is fully ready for production and is designed for small calculation clusters in industrial application.

Documentation

Piston Ring Oil Transport I | Oiltransportation through piston rings | Project No. 1124 + 1128

Piston Ring Oil Transport II | Oiltransportation through piston rings | Project No. 1197

Piston Ring Oil Transport - Glass Liner | Visualisation by glass window | Project No. 1210

Piston Ring Oil Transport - Glass Liner II | Visualisation by glass window | Project No. 1302

Themis

Status
Finalised

Programme
Public & FVV Funding

Budget
2.340.000‬,00 EUR

Time Period
2012-11-01 to 2015-04-30 Part I
2015-07-01 to 2016-12-31 Part II
2015-12-31 to 2017-06-29 Glass Liner | Part I
2017-12-31 to 2018-12-30 Glass Liner | Part II

Research Association for Combustion Engines (FVV) eV

Lyoner Strasse 18
60528 Frankfurt am Main
Germany

German Federation of Industrial Research Associations (AiF) e. V.

Bayenthalgürtel 23
50968 Cologne
Germany

Federal Ministry for Economic Affairs and Energy (BMWi)

Scharnhorststrasse 34-37
10115 Berlin
Germany

Industrie

Dr. Arnim Robota
Federal Mogul Burscheid GmbH

Forschungsstellen

1 | Institute of Internal Combustion Engines (LVK), Department of Mechanical Engineering - Technical University of Munich (TUM)

Head of Research:
Prof. Dr.-Ing. Georg Wachtmeister

2 | Institute for Powertrain and Automotive Technology (iaf) - University of Kassel

Head of Research:
Prof. Dr.-Ing. Adrian Rienäcker

3 | Chair of Aerodynamics and Fluid Dynamics (FG LAS), Institute of Transport Technology, Mechanical Engineering, Electrical and Energy Systems (Faculty 3) - Brandenburg University of Technology Cottbus - Senftenberg (btu)

Head of Research:
Prof. Dr.-Ing. Christoph Egbers

4 | Institute of Analytical Mesaurement Hamburg - IAM-Hamburg eV

Head of Research:
Prof. Dr.-Ing. Gerhard Matz

Technical University of Munich (TUM)

Institute of Internal Combustion Engines (LVK)

Arcisstrasse 21
80333 Garching
Germany

University of Kassel

Institute for Powertrain and Automotive Technology (iaf)/Department of Machine Elements and Engineering Design (MT)

Mönchebergstrasse 7
34125 Kassel
Germany

Hamburg University of Technology (TUHH)

Institute of Measurement Technology

Harburger Schloßstr. 20
21079 Hamburg
Germany

Hamburg University of Technology (TUHH)

Institut für Analytische Messtechnik Hamburg - IAM-Hamburg e.V.

Peutestraße 53A
20539 Hamburg
Germany

Brandenburg University of Technology Cottbus-Senftenberg

Institut für Verkehrstechnik/Lehrstuhl Aerodynamik und Strömungslehre (LAS)

Siemens-Halske-Ring 14
03046 Cottbus
Germany

Deputy Managing Director

Martin Nitsche

FVV
+49 (0) 69 6603 1345
+49 (0) 69 6603 2345


Research Association for Combustion Engines eV

Lyoner Strasse 18
60528 Frankfurt am Main
Germany
T +49 69 6603 1345