| Popis: |
To meet the needs of higher power, lower weight and better emissions IC engines, component manufacturers develop new materials, coatings and surface technologies (e.g. surface texture). In this paper methodologies have been developed for comparing & ranking interface materials with custom-built rigs built in GE Global Research, Bangalore for large sized IC engines. This work will discuss the three methodologies developed using: i) Journal Bearing Rig ii) Piston-Liner Rig and the iii) Valve-seat rig. The Journal bearing Rig can be spun to engine linear speeds with lubricant heated to engine oil temperature. The loading is performed using a hydraulic system. Seizure, steady state wear and start stop tests can be performed on this rig. The piston liner rig can accommodate a section of the liner and ring from an actual engine. The combination of the pneumatic mechanism and the 2-axis load cell can load and measure the normal load & frictional load. The piston ring-liner simulates interface hot engine temperatures and contact pressures at TDC/BDC. Scuffing & wear tests can be performed with this test rig to compare scuffing limits and steady state wear rates. The valve-seat rig fixture is built within a MTS frame and can accommodate small sections of the actual engine valve and seat. Normal load and the fretting stroke is simulated using MTS hydraulic system A furnace is used around the fixture to simulate higher temperatures. Case studies comparing & ranking different coatings/repair coatings and oil additives etc. will be presented in this work to showcase the effectiveness of the methodology. Tests using this methodology can be typically performed in 10 % of time & cost of actual engine test. |
