Richard Mittler

UNDERSTANDING THE FUNDAMENTALS OF PISTON RING AXIAL MOTION AND TWIST AND THE EFFECTS ON BLOW-BY

Advances in modern engine development are becoming more and more challenging. The intense increase of thermal and mechanical loads interacting in the combustion chamber as a result of higher power density requires perfecting the function of piston rings especially with regard to emission reduction technology. The major obstacle to predicting blow-by and oil consumption is the behavior of the piston rings under engine operating conditions. Design and functionality of a piston ring are highly influenced by the operating conditions. To understand the fundamentals of ring behavior and in this way the effects on blow-by and oil consumption, an analytical tool has been developed to transform the physical boundary conditions of engine kinematics and ring design into a reliable simulation. This paper describes the physical basics of ring movement under dynamic loading conditions and gives an overview of the results. It also was necessary to validate the model with real engine measurements to understand the fundamentals of ring design as a function of the described mathematics.Copyright

Detailed 3D ring pack analysis

Demanding emission targets for combustion engines must be fulfilled in increasingly shorter development cycles. Federal-Mogul utilizes the 3D Ring Pack Analysis to quickly and precisely simulate piston rings during a position change. An application example with a reduction of 15 % blow-by gas shows the potential of possible optimization measures.

Optimization of Tribodynamic Effects to Improve the Reduction Potential of Particulate Matter Concentrations in the Exhaust Gas of Large Two Stroke Marine Diesel Engines

Understanding tribodynamic effects is crucial when aiming to reduce lube oil consumption and related exhaust gas emissions. This report briefly describes the lubrication concept of large two stroke marine diesel engines and different contributors to the lube oil balance of such an engine. Addressing possible measures to influence the contribution of lubrication system parameters on exhaust gas emissions requires a detailed analysis of possible actions to achieve the expected improvement. Activities to enhance lubrication system performance concentrate on: Modifications of relevant engine components The application of experimentally gained data to support computational simulation models The application of suitable validation approaches This report in particular highlights piston ring pack optimizations on basis of computational simulation. One major step in developing a new piston ring pack dynamic simulation tool was achieved by implementing two stroke engine specific measurement results of general engine performance data, as well as complex information of triboand gas-dynamic effects on piston ring motion and lube oil film. This report consequently describes experiments which were performed to validate piston ring pack performance in a full scale engine test and lead to improved understanding of tribodynamic effects.

Einfluss der Auslegung von Kolbenringen auf das Formfüllvermögen in thermisch und mechanisch hoch beanspruchten Motoren

Trotz Einsatz neuer Werkstoffe und Beschichtungen besteht im Zylinder die Gefahr einer lokalen thermischen Uberlastung an den Kolbenringlaufflachen. Der Beitrag der Federal Mogul Burscheid GmbH beschreibt ein Rechenmodell zur Bestimmung des Anpressdrucks von Kolbenringen mit konstanter und inkonstanter Wanddicke. Damit erhalt man eine Aussage zur Fahigkeit des Kolbenrings, sich unrunden und thermisch belasteten Zylindern anzupassen. Auf Basis dieser Rechenergebnisse wurden Designvarianten zur Optimierung des Motorbetriebs abgeleitet und entwickelt.

Optimization of the piston assembly friction

The present paper points out that improvements of the piston assembly friction necessitate a high level of system knowledge, which requires experimental investigations. Therefor the self-developed research engine of the Institute of Internal Combustion Engines of the Technical University of Munich is introduced. Besides the high accuracy of the measurement device a well-defined testing procedure is important to analyze the influence of specific design changes of the piston assembly on their frictional behavior. The presented testing methodology developed by the Institute guarantees the comparability of different testing configurations.

Detaillierte 3D-Ringpaketanalyse

Anspruchsvolle Emissionsziele mussen bei Verbrennungsmotoren in immer kurzeren Entwicklungszyklen erreicht werden. Federal-Mogul nutzt die 3D-Ringpaketanalyse, um die Dynamik von Kolbenringen beim Anlagewechsel schnell und prazise nachbilden zu konnen. Eine Beispielanwendung zeigt mit 15 % weniger Blow-by-Gas das Potenzial moglicher Optimierungsmasnahmen.

The effect of piston ring design on conformability in highly thermally and mechanically loaded engines

Even the use of the latest tools and materials cannot eradicate the danger of local thermal overload on the piston ring running surface. This article describes a computing model for determining the pressure against the cylinder wall of piston rings with constant and inconstant wall thicknesses and results regarding the capability of the piston ring to adapt to unround and thermally and mechanically loaded cylinders. Design variations for optimizing engine performance were deduced and developed on the basis of these computing results.