Development of New CNG-Gasoline (Bi-fuel) Lubricant, by Taxi Fleet Screening Test and Field Trial in Thailand 2012-01-1622

This formulation development comprised of two rigorous field trial phases conducted in Bangkok, Thailand. The first phase involved the screening of various candidate formulations developed by PTT in a fleet of high mileage bi-fuel taxi vehicles. A final candidate formula was selected for further proof of performance in the second phase controlled field trial. This second phase controlled field trial was carried out on five new bi-fuel vehicles and two new conventional gasoline vehicles, and at an extended ODI of up to 25,000 km as compared to original recommended 10,000 km ODI. The engines of 3 field trial vehicles were inspected at the end of trial. The CNG-gasoline bi-fuel engines were observed to in excellent condition with minimum sludge & deposit issue, as well as an excellent used oil analysis (UOA) result throughout the trial. Despite the trial was run at extended ODI, the nitration/oxidation number and total acid number (TAN) growth/total base number (TBN) depletion were well-controlled. In addition, the candidate formula exhibited minimal engine wear, superior piston deposit ratings, as well as rendering potential fuel economy benefit. The candidate formula has shown to exceed the performance requirement for the latest CNG-gasoline (bi-fuel) passenger cars, and even for high mileage bi-fuel taxi vehicles under severe driving conditions in Bangkok, Thailand.