One of the most attractive ways to tackle vehicle engine's inefficiencies is the use of Low Viscosity Engine Oils (LVEO). Adopted some decades ago for their use in the Ligh Duty segment, LVEO are now reaching the Heavy Duty segment.

In this study, a comparative fuel consumption test, where a LVEO performance is evaluated on an urban compressed natural gas buses fleet is portrayed. Then the friction performance of the same oils are studied on a Cameron-Plint tribometer, on an adapted twin disc tribometer to simulate journal bearing friction and on a Ball-on-Disc rig, using real engine parts in the former and the same set of engine oils used during the fleet test.

Results show a fuel consumption reduction in the fleet test and corresponding friction reduction in the tribometers when LVEO are used.