| abstract |
The present invention relates to a method of operating a spark ignition four-stroke internal combustion engine (10) having a valve train (14) and a crankcase (12) and equipped with an exhaust gas aftertreatment device (20). Operating an engine using a gasoline fuel composition, wherein the exhaust gas from the engine operation is advanced through an aftertreatment device 20; (B) the amount of phosphorus added to the first lubricant composition by the extreme pressure additive in the first lubricant composition optionally containing an extreme-pressure additive exceeds about 0.04% by weight, based on the weight thereof. Lubricating the crankcase 12 using a first lubricating oil composition, wherein the crankcase 12 comprises no metal and phosphorus; (C) lubricating the valve train using a second lubricant composition. |