Aftermarket Fuel Additives and their Effects on GDI Injector Performance and Particulate Emissions

Gasoline Direct Injection (GDI) fuel injectors are fouled when carbon deposits build-up on the injector tip, impeding fuel droplet atomization and dispersion. These issues, if left untreated, can lead to losses in engine power and fuel economy, as well as increased emissions of particulate matter (PM). Bottled aftermarket gasoline detergents are commonly used to remove deposits and restore injector performance. A performance analysis of three classes of bottled gasoline additives was performed, focusing on products that do not contain nitrogen-based detergents; products containing nitrogen-based detergents; and a new class of gasoline detergent formulations designed specifically for GDI injector fouling. Analyses completed included additive chemical analysis to confirm the presence of nitrogen-based gasoline detergents in the bottled product; engine testing to establish injector clean-up performance quantified through injected fuel spray volume as well as visual inspection of reduced injector tip deposits; and particulate matter mass measurements to assess the emissions impacts due to deposit build-up. The resultant analyses show nitrogen-based gasoline detergents are most effective in reducing injector fouling. Further, a new formulation, designed specifically to reduce injector fouling in GDI engines results in the highest level of injector cleanliness and reductions in PM emissions.