Development of lean stratified turbocharged gasoline engines for 2018 SOP

In order to reduce fuel consumption and CO2 emissions, engine downsizing with boosting and downspeeding are among the most promising solutions currently envisaged. Those solutions have impact on NOx and PM emissions in GDI engines. In order to mitigate this impact, Ricardo is developing the T-SGDI concept which uses spray guided lean stratified operation. The application of emissions control systems to advanced lean DI gasoline engines will require a combination of knowledge-transfer from diesel LNT experience, traditional gasoline 3-way catalysis and new considerations of trapping media for particle and PM control. The authors will discuss how these technologies can be combined and some of the challenges and opportunities that are likely to arise.
In parallel to the development of the combustion process, there are also developments in PM characterisation of GDI research engine using Differential Mobility Spectrometry (DMS). The tests have shown the influence of fuel injection control parameters and fuel injector concepts on PM characteristics. In the context of the European Particle Measurement Programme (PMP), a lower PM cut-off limit has been investigated. The results will be reported in the article.
The DMS results are also compared to different commercial PMP results.
Finally the article will present the energy balance showing the reasons for BSFC improvement with T-SGDI concept and also the CO2 walk for a D-segment vehicle (Sedan) using the T-SGDI engine (2L turbo SGDI rated at 200 kW) and other technologies applied on the engine (friction, thermal management) and vehicle (weight and aerodynamic drag) in order to reach 120 gCO2/km over NEDC.