Effects of Dual Port and Direct-Injection Technology on Combustive Emissions from Light-Duty Gasoline Vehicles 2019-01-0999
Dual injection fuel systems combine the knock and fuel economy benefits of gasoline direct injection (GDI) technology with the lower particulate emissions of port fuel injection (PFI) systems. For many years, this technology was limited to smaller-volume, high-end, vehicle models, but these technologies are now becoming main stream. The combination of two fuel injection systems has an impact on the combustion emission composition as well as the consistency with which these can be measured. Understanding the impact of these changes is essential for fuel and fuel additive companies, automotive companies, and aftertreatment developers.
This paper describes the effects of dual injection technology on both regulated and non-regulated combustion emissions from a 2018 Toyota Camry during several cold-start, 4-bag FTP cycle. The vehicle was tested both with and without aftertreatment to continually monitor the relative duty of each injection system. A specifically designed sample train was used for the collection of low concentrations of polycyclic aromatic hydrocarbons (PAH) and other high molecular weight hydrocarbons. These compounds were differentiated by particulate and semi-volatile phases in the exhaust using this sampling technique which allows the phases to be separated. Particulate phase compounds were collected on 508 mm X 508 mm filters, and large traps filled with XAD resin were used for trapping the semi-volatile hydrocarbons. After extraction to concentrate the samples and remove interferences, these samples were analyzed by gas chromatograph time of flight mass spectrometer (GCxGC-TOFMS) to speciate the unresolved complex mixture of the various hydrocarbons and to identify changes in exhaust composition resulting from the dual injection technology.
Robert Fanick, Svitlana Kroll, Andre Swarts, Shraddha Quarderer