Due to increasing interest in air quality concerns, worldwide legislation towards lower particle emissions is getting more and more stringent. Because of this, the development towards even cleaner internal combustion engines (ICE) with Spark Ignition (SI) is of upmost importance. Along with the development targeting higher efficiency and specific power output, Direct Injection (DI) technology became more and more important than Port Fuel Injection (PFI) and is one of the main SI engine development fields. SI engine mixture preparation (PFI or DI) and combustion produce much lower particle raw emissions than Diesel engines, but these emissions also have to be reduced to fulfill worldwide legislation and customer expectations.
In this paper the focus lies on the analysis and development methods used to drastically reduce particle emissions in a gasoline-fueled DI SI engine. Relevant steps like engine design, spray-targeting and quasi-dimensional simulation over standard and advanced particle emissions measuring technology and combustion chamber optical access analysis are presented and particle reduction examples are shown on relevant real driving operation points.
Results show that there are numerous levers to reduce particle emissions in real driving relevant operation points and that a consequent global engine design and development allow for efficient optimization.