题目: Air reactivity on the demand for Low Temperature Combustion Engine
Fabrice Foucher is a professor in the Mechanical Technology Department and researcher at the PRISME Laboratory, University of Orléans, France. He is the head of the Energy, Combustion and Engine group at the PRISME laboratory and the leader of the Joint Lab with Peugeot-Citroen Company. His research interests include combustion, engines, new combustion modes, fuels and optical diagnostics. He has directed or co-directed 14 PhD students, published more than 80 peer-reviewed journal articles and has an H-factor of 21 based on the Scopus database.
Gasoline Compression Ignition (GCI) engine based on Partially Premixed Combustion (PPC) showed potential to match Compression Ignition (CI) like efficiency with reduced pollutant emission. Injection strategy allows controlling the combustion event actuating on fuel stratification, while the autoignition resistance of gasoline improves fuel-air mixing process, so that local equivalence ratios (ϕ) and flame temperatures responsible of NOx and soot production are avoided. To control the phasing of the combustion, the influence of several parameters, as uncooled Exhaust Gas Recirculation (EGR), intake pressure, Variable Valve Train to promote gasoline autoignition by trapping hot residual gases into cylinder timing or low octane number have been study by many authors. However, costly engine layout or the use of low octane gasoline not available on the market are necessary to overcome low reactivity of gasoline, discouraging automotive producers to run over GCI way.
Another way to enhance autoignition propensity of gasoline is represented by seeding the intake of the engine with oxidizing chemical species to change the reactivity of the air. Many works have been conducted in under HCCI conditions, demonstrated that air reactivity on the demand strongly promotes premixed combustion of a large variety of fuel as PRF blends, Alcohol, Natural Gas and over a large range of engine operating conditions including nitrogen and Exhaust Gas Recirculation (EGR) dilution. Small concentration of O3 molecules seeding the intake of the engine were responsible of strong acceleration of combustion phasing. GCI combustion, ozone seeding and interaction with residual trapped gases are presented. We demonstrate that this strategy allow to control the autoignition of high octane number gasoline grade fuel, increase the efficiency of the engine and tends toward very low pollutant emission at the exhaust.