Advanced piston technologies for gasoline and diesel engine applications to meet EU6 emission norms

Abstract

The Indian government announced that the country would adopt Bharat Stage VI (Euro VI) norms by 2020, skipping Euro V. In order to meet EU6 emission targets, the technologies which are available for Gasoline vehicles are; Gasoline Direct Injection (GDI) engine, Three-Way Catalytic Converter (TWC), Exhaust Gas Recirculation (EGR) and Universal wide range oxygen sensors. The vehicles with diesel engines having Common Rail Direct Injection systems (CRDI) with variable fuel timing and metering strategies and Injection pressure is up to 2100 Bar, Variable Geometry Turbocharger (VGT), cooled high-pressure EGR, Diesel Oxidation Catalysts (DOC), diesel particulate Wall-flow type filter (DPF), Lean-NOx Traps (LNT) technology (<3.0 L) [Sanchez et al., Estimated Cost of Emission Reduction Technologies for Light-Duty, 2012, 4], Selective Catalytic Reduction (SCR) technology (>3.0 L) are used in combination to control the emissions. For gasoline applications with high peak cylinder pressures (PCP) and high specific power output (kW/L), the pistons can include a cooling gallery and/or top ring groove reinforcement with Hard Anodising or Ring carrier. To handle the high loads and particulate matter that are being re-circulated into the engine cylinder due to exhaust gas recirculation system to control NOx formation. Diesel engine pistons include features to enhance bowl rim life like TopCast or Bowl rim remelting is applied to refine the micro structure to achieve higher fatigue strength at elevated temperatures, and selective area Hard anodising. For very highly loaded applications, MAHLE Monotherm, Monoweld or Monolite Steel pistons are used.