Bench-top Lubricity Evaluator Correlation with Military Rotary Fuel Injection Pump Test Rig

U.S. military vehicles and equipment can be exposed to poor lubricity fuels. Lubricity-improving additives (LIA) are utilized to remedy fuel lubricity to satisfactory levels. The military is interested in developing an affordable and fast bench-top lubricity evaluator capable of measuring fuel lubricity and improvements provided by LIA in order to replace the expensive and time consuming Military Rotary Fuel Injection Pump Test Rig. Previous tests have shown that certain bench-top lubricity evaluators are sensitive to LIA and correlate well with the pump test rig but lack precision. In an effort to improve the viability of bench-top evaluators for measuring fluid lubricity, a parameter study was conducted to determine if modifications to the bench-top lubricity methodology, apparatus, and operating conditions would improve the sensitivity and precision. Data from the study suggests that improved precision can be achieved by ensuring uniform contact between test surfaces (ball and disks), and improved sensitivity by increasing test fluid temperature to 40°C or 50°C. Implementing these modifications to the bench-top lubricity evaluator will increase the differentiation between a “poor” and “good” lubricity fluid.