Optimierung des tribologischen Systems Kolbenring-Zylinderlaufbahn von stationären Groß-Gasmotoren

Translated title of the contribution: Optimization of the tribological piston ring-cylinder liner system of stationary large gas engines.

Jürgen Schiffer

Research output: ThesisDoctoral Thesis

Abstract

Nowadays in engine development, improvement in performance and the concurrent ambition for efficiency, reliability and reduction of emissions due to regulations, necessitate continuous optimization of the entire engine and its individual components. This process leads to a steady increase in the brake mean effective pressure BMEP, which results in higher mechanical, thermal and tribological loads, close to the performance limit of the piston ring-cylinder liner system. Furthermore, frequent inclusions of wear particles within the engine could lead to further negative effects on the functioning of the system. Summing up all these facts, it is clear, that a systematic approach for optimizing the tribological system of piston ring-cylinder liner is required. Within this present work, the operating modes of cylinder liners made out of gray cast irons and thermochemically modified steels have been systematically investigated. Tribological tests have been performed on the model scale system “ring-on-liner” which features equivalent function and damage behavior as in the real component. In combination with test strategies developed in this work, and extensive analytical investigations, the small differences within the system under engine specific parameters can be visualized. The obtained test results lay the basis for generation of material specific models for function and damage. Tribological tests and analytical investigations show that thermochemically modified steel cylinder liners show low wear when used in large stationary gas engines. Besides a high thermal and mechanical stability of the piston ring-cylinder liner system, the emergency running conditions following from deficient lubrication can be improved. In addition, after the running-in, the modified cylinder liners show good long term behavior with high wear resistance. An oxide layer on the surface serves as running-in layer and reduces the energy consumption during the running-in phase. Moreover, the oxide layer facilitates the formation of wear reducing additive layers. The extensive results of this work can be transferred on to the real component and lay the basis for validation on the engine test rig, and furthermore provide required parameters for future development processes of the piston ring-cylinder liner system.
Translated title of the contributionOptimization of the tribological piston ring-cylinder liner system of stationary large gas engines.
Original languageGerman
QualificationDr.mont.
Supervisors/Advisors
  • Godor, Istvan, Co-Supervisor (internal)
  • Schenk, Johannes, Assessor B (internal)
  • Grün, Florian, Assessor A (internal)
Publication statusPublished - 2014

Bibliographical note

embargoed until null

Keywords

  • gas engine
  • piston ring
  • cylinder liner
  • gray cast iron
  • thermochemically modified steel
  • model scale
  • ring-on-liner
  • wear resistance
  • system stability
  • tribofilm

Cite this