Low ash, low phosphorus and low sulfur engine oils for internal combustion engines

In the method of combusting an ultra low sulfur fuel in an internal combustion engine lubricated with a lubricating composition, the improvement comprising using as the lubricating composition one comprising:

• (a) a major amount of a base oil of lubricating viscosity and having a sulfur content below about 300 ppm based on the weight of base oil;
• (b) about 0.5 wt % to about 10 wt % of a boron-containing ashless dispersant;
• (c) about 0.05 wt % to about 5.0 wt % of a molybdenum containing friction reducing additive;
• (d) about 0.05 wt % to about 5.0 wt % of at least one kind of metal-type detergent selected from the group consisting of sulfonates, phenates and salicylates;
• and
• (e) 0.10 wt % to 0.75 wt % of a zinc dialkyl dithiophosphate.

A lubricating oil composition comprising:

• (a) a major amount of an oil of lubricating viscosity and having a sulfur content below about 300 ppm sulfur;
• (b) about 0.5 wt % to about 10 wt % of a boron-containing polyisobutylene succinic ester-amide ashless dispersant;
• (c) about 0.05 wt % to about 1.50 wt % of a trinuclear molybdenum compound having the formula Mo3S7(dtc)4, Mo3S4(dtc)4 and mixture thereof where dtc represents diorganodithiocarbamate ligands;
• (d) about 0.05 wt % to about 5.0 wt % of at least one metal-type detergent selected from the group consisting of calcium, magnesium and barium sulfonates, phenates and salicylates;
• and
• (e) 0.10 wt % to 0.75 wt % of a zinc dithiophosphate wherein the alkyl groups are the same or different alkyl groups of from 3 to 20 carbon atoms, said composition having a sulfur content of less than 0.18 wt %, a phosphorous content of less than 0.048 wt % and a sulfated ash of less than 0.5 wt %.

A method for reducing friction and the wear in an oil lubricated engine combusting an ultra low sulfur fuel, the method comprising lubricating the engine under conditions of use with a lubricating composition comprising:

• a major amount of an oil of lubricating viscosity having a sulfur content below about 300 ppm sulfur;
• about 0.5 wt % to about 10 wt % of a boron-containing ashless dispersant;
• about 0.05 wt % to about 1.5 wt % of a molybdenum containing friction reducing additive;
• about 0.05 wt % to about 5.0 wt % of at least one kind of metal-type detergent selected from the group consisting of sulfonates, phenates and salicylates;
• and
• wt % to 0.75 wt % of a zinc dithiophosphate.