Improving sustainability by enhanced engine component lifetime through friction modifier additives in fuels

Engine test rig runs with a standard and a friction modifier containing premium fuel using an artificially altered close to end-of-life oil were conducted. Friction modifier and antiwear additives were completely degraded in the oil at the start of the test. Radioisotope activated piston rings were utilized in the engine, which allowed wear determination via radioisotope concentration measurements. Additionally, 3D topography of the piston rings and determination of the iron content in the engine oil were performed to determine wear that occurred during the test.The engine test runs resulted in comparable fuel dilution with standard and premium fuels, namely 0.84 - 0.98 m% and 0.69 - 0.80 m% respectively, which indicates comparable physical interactions between the engine oil and the two fuel formulations.All 3 independent methods for wear measurement confirmed that the premium fuel containing friction modifier results in an overall superior wear protection compared to standard fuel. Mass spectrometry of oil aliquots from the engine test rig runs showed an accumulation of friction modifier in the end-of-life engine oil, which explains the better tribological characteristics observed in this case. Accordingly, application of friction modifier in fuels can lead to increased oil change intervals since the wear protection is acceptable even in case of an end-of-life oil condition and potentially improved engine component lifetime. Both factors offer economic and environmental benefits.