Volume 4, Issue 10 (November 2007)
ROBO—A Bench Procedure to Replace Sequence IIIGA Engine Test
A constant quest but a difficult goal is replacement of expensive and lengthy engine tests with more cost effective bench tests. This paper will report on development of a bench test, the ROBO, as a potential replacement for the Sequence IIIGA, an oxidative oil thickening engine test now part of ILSAC GF-4 specifications. Sequence IIIGA, a gasoline fueled engine running under severe conditions, is used to condition oils prior to determining TP-1 MRV viscosity, a cold temperature and low shear rate measurement. After Sequence IIIGA conditioning, candidate oils must meet SAE J300 pumpability limits at no more than 5°C warmer than its original SAE W grade. The ROBO bench procedure has been developed to potentially replace Sequence IIIGA engine aging by mimicking, to the degree possible, oxidative conditions found in the engine conditioning procedure. ROBO conditions were developed by employing the three Sequence IIIG ASTM matrix oils and comparing their used oil rheologies from multiple Sequence IIIG and ROBO runs. The results from the final ROBO conditions compare well not only for TP-1 MRV but also for KV 40°C and CCS. To further test the correlation of bench to engine conditioning, a set of diverse oils (various SAE viscosity grades and DI chemistries) have been examined; these viscometric data from ROBO and Sequence IIIG also compare favorably with only a few anomalies. Finally, the status of industry acceptance of ROBO will be discussed.