Lubricating oil consumption on the standard road cycle

Automobile manufacturers strive to minimize oil consumption from their engines due to the need to maintain emissions compliance over the vehicle life. Engine oil can contribute directly to organic gas and particle emissions as well as accelerate emissions degradation due to catalyst poisoning. During the Department of Energy Intermediate Ethanol Blends Catalyst Durability program, vehicles were aged using the Standard Road Cycle (SRC). In this program, matched sets of three or four vehicles were acquired; each vehicle of a set was aged on ethanol-free retail gasoline, or the same base gasoline blended with 10, 15, or 20% ethanol (E0, E10, E15, E20). The primary purpose of the program was to assess any changes in tailpipe emissions due to the use of increased levels of ethanol. Oil consumption was tracked during the program so that any measured emissions degradation could be appropriately attributed to fuel use or to excessive oil consumption. In addition, excessive oil consumption was used to help diagnose potential engine maintenance problems. This paper details the results of analysis of the available oil consumption records from this program. Oil consumption levels for the properly-functioning light-duty vehicles aged on the SRC in this program range from 0.015 to 0.090 g/km. On a fuel specific basis (g oil/kg fuel burned) results range from 0.16 to 1.14 g/kg (0.016% to 0.114 %). Results indicate no statistically significant effect of fuel ethanol level on oil consumption.