Gaseous and Particulate Emissions from a Vehicle with a Spark-Ignition Direct-Injection Engine

Particulate and gaseous emissions from a Mitsubishi Legnum GDI™ wagon were measured for FTP-75, HWFET, SC03, and US06 cycles. The vehicle has a 1.8-L spark-ignition direct-injection engine. Such an engine is considered a potential alternative to the compression-ignition direct-injection engine for the PNGV program. Both engine-out and tailpipe emissions were measured. The fuels used were Phase-2 reformulated gasoline and Indolene. In addition to the emissions, exhaust oxygen content and exhaust-gas temperature at the converter inlet were measured.

Results show that the particulate emissions are measurable and are significantly affected by the type of fuel used and the presence of an oxidation catalyst. Whether the vehicle can meet the PNGV goal of 0.01 g/mi for particulates depends on the type of fuel used. Both NMHC and NO_x emissions exceed the PNGV goals of 0.125 g/mi and 0.2 g/mi, respectively. Meeting the NO_x goal will be especially challenging. The vehicle had no difficulty meeting the CO emissions goal of 1.7 g/mi. The 200-s catalyst warm-up time is a major reason for the failure to meet the PNGV goals for NMHC and NO_x. In addition, the presence of excess oxygen in the exhaust stream increases the difficulty of reducing NO_x in the catalytic converter.