Durability Study of a Light-Duty High Pressure Common Rail Fuel Injection System Using E10 Gasoline 2020-01-0616

A 500-hour test cycle has been used to evaluate the durability of a prototype high pressure common rail injection system operating up to 1800 bar with E10 gasoline. Some aspects of the original diesel based hardware design were optimized in order to accommodate an opposed-piston, two-stroke engine application and also to mitigate the impacts of exposure to gasoline. Overall system performance was maintained throughout testing as fueling rate and rail pressure targets were continuously achieved and no physical damage was observed in the low-pressure components. Injectors showed no deviation in their flow characteristics after exposure to gasoline and high resolution imaging of the nozzle spray holes and pilot valve assemblies did not indicate the presence of cavitation damage. The high pressure pump did not exhibit any performance degradation during gasoline testing and teardown analysis after 500 hours showed no evidence of cavitation erosion. Despite the lack of lubricity-improving additives in the gasoline, all other fuel-wetted components survived the test cycle without any signs of abnormal contact wear. Fuel and lubricating oil analysis conducted on samples taken at 50-hour intervals confirmed that there was minimal oil-in-fuel or fuel-in-oil dilution throughout most of the cycle. In summary, these results represent an important and positive step forward in assessing the suitability of high pressure fuel system hardware for light-duty gasoline applications.