Lubricating oil compositions with improved wear performance and soot dispersancy

A concentrate comprising or resulting from the admixing of:

• from 1 to less than or equal to 50 wt. % of one or more base oils;
• from 1 to 30 wt. %, based upon the weight of the concentrate, of one or more of the functionalized polymers of the composition comprising an amide, imide, and/or ester functionalized partially or fully saturated homopolyisoprene containing one or more pendant amine groups and having an Mn of 25,000 to 100,000 g/mol (GPC-PS) and at least 50% of 1,4-insertions prior to functionalization having:
• i. an Mw/Mn of less than 2,
• ii. a Functionality Distribution (Fd) value of 3.5 or less,
• iii. an Mn of 10,000 g/mol or more (GPC-PS) of the polymer prior to functionalization, and
• iv. an average functionality (Fv) of 5 to 20 functional group grafts/polymer chain;
• from 2 to 20 wt. % of an overbased magnesium based detergent with a Total Base Number (KOH/g) greater than or equal to 9 and less than or equal to 500;
• from 1 to 20 wt. % of an overbased calcium based detergent with a Total Base Number (KOH/g) greater than or equal to 9 and less than or equal to 500;
• and
• from 2 to 40 wt. % of one or more, optionally borated, higher molecular weight polyisobutylene succinimide (PIBSA-PAM) dispersant (Mn 1600 g/mol or more), and one or more, optionally borated, lower molecular weight polyisobutylene succinimide (PIBSA-PAM) dispersant (Mn less than 1600 g/mol).

A method of making a lubricating oil composition comprising combining:

• (1) an oil of lubricating viscosity at greater than 50 wt. % of the composition comprising a Group II base oil, a Group III base oil, a Group IV base oil, or combinations thereof;
• (2) a functionalized polymer at from 0.1 to 20 wt. %, of the composition comprising an amide, imide, and/or ester functionalized partially or fully saturated homopolyisoprene containing one or more pendant amine groups and having an Mn of 25,000 to 100,000 g/mol (GPC-PS) and at least 50% of 1,4-insertions prior to functionalization having:
• i. an Mw/Mn of less than 2,
• ii. a Functionality Distribution (Fd) value of 3.5 or less,
• iii. an Mn of 10,000 g/mol or more (GPC-PS) of the polymer prior to functionalization, and
• iv. an average functionality (Fv) of 5 to 20 functional group grafts/polymer chain;
• (3) an overbased calcium based detergent with a Total Base Number (KOH/g) greater than or equal to 9 and less than or equal to 500 and at treat level to deliver at least 400 ppm by weight of calcium to the composition;
• (4) an overbased magnesium based detergent with a Total Base Number (KOH/g) greater than or equal to 9 and less than or equal to 500 and at treat level to deliver at least 500 ppm by weight of magnesium to the composition;
• (5) one or more, optionally borated, higher molecular weight polyisobutylene succinimide (PIBSA-PAM) dispersant (Mn 1600 g/mol or more), and
• (6) one or more, optionally borated, lower molecular weight polyisobutylene succinimide (PIBSA-PAM) dispersant (Mn less than 1600 g/mol), wherein the treat level of the combination of the higher molecular weight PIBSA-PAM and lower molecular weight PIBSA-PAM is from 4.0 to 10.0 wt. % of the composition, and wherein the treat level of the higher molecular weight PIBSA-PAM is from 0.5 to 8.0 wt. % of the composition;
• and
• wherein the lubricating oil composition has a total sulfated ash of less than or equal to 1.0 wt. %, a kinematic viscosity at 100° C. of 5 to 20 cSt, a total phosphorous level of less than or equal to 0.120 wt. %, and a total sulfur level of less than or equal to 0.4 wt. %, and
• wherein the lubricating oil composition provides a Cummins ISM oil filter delta pressure (OFDP) test result at 150 hours of less than 30 kPa.