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Exhaust Gas Recirculation - EGR - is a well-known technique to reduce NOx and it’s been applied on Diesel engines for a long time. Later studies and application found that other benefits can be achieved with PFI and GDI gasoline engines, such as pumping loss minimization and efficient knock control. Variable valve actuation valve-trains brought broader application possibilities as it enables full internal EGR control without external paths, high precision and response, as required on transient work modes. Comprehensive investigation on PFI and GDI Spark Ignition engines with external Hot EGR and Cooled EGR are widely available. However, variable valve actuation EGR control review on a flexfuel application is not well explored, and this paper is aimed at doing such.

Low-speed-pre-ignition (LSPI) presents a great challenge for developing smaller, more efficient internal combustion engines. Current research focuses on understanding the causes of LSPI and developing strategies to mitigate its intensity or eliminate it completely. On this paper, the effect of different LSPI mitigation strategies on emission levels is evaluated. For this purpose, a 1.0 naturally aspirated port fuel injection (PFI) engine was used. The research engine suffers from LSPI phenomena under rotation speeds below 1000 rpm and high loads. Operation parameters were controlled using a fully instrumented dynamometer cell with incylinder pressure monitoring. The occurrence of LSPI was determined by using in-cylinder pressure data paired with in-cylinder light intensity using an instrumented spark plug with optical access to the combustion chamber. The emission levels of CO, CO2, NO, NO2 amd HC were measured using a real-time emission analysis stand.