Novel approaches to improve the gas exchange process of downsized turbocharged SI engines – A review

This paper will first briefly review knowledge of the current state of the art technologies that are in production as opposed to approaches that are currently only being investigated at a research level. Next, more novel methods of the gas exchange process are introduced to identify the improved synergies between the engine and the boosting machine. The major findings to improve the gas exchange process that emerge from this review are comprised of four aspects (depending on the location where the novel technologies are implemented): charge air pressurization/de-pressurization improvement, combustion efficiency enhancement within the chamber, valve event associated development and exhaust system optimization. Although the interaction between these technologies on different aspects of the gas exchange process was found to be highly complex the optimization or the combination of these technologies is anticipated to further improve a downsized turbocharged SI engine’s performance.