WorkPackage 2

Determination of ignition characteristics of 2G-biofuels and conventional fuels

With the development of new engine technologies or combustion strategies (HCCI, LTC, etc.), the ignition characteristics of fuels are extensively studied. Research octane number (RON) and motor octane number (MON) have been widely used to represent ignition characteristics of fuels as ignition index. But, these indexes represent more knocking tendencies than fuels’ ignition characteristics. Moreover, their application to reformulated fuels is limited. Ignition delay times have been measured in shock tubes and rapid compression machines (RCM) for years. Whereas ignition processes in shock tubes and RCM have been previously modelled as homogeneous combustion at constant volume, it was recently reported that in shock tubes, ignition may be strongly affected by uncontrollable disturbances such as combustion-gas dynamics coupling, or fluid dynamic non-idealities[1]; other complications appear in RCM: heat loss to chamber wall and vortices generated by piston movement. It is then preferable to investigate fuels ignition characteristics using a better characterised reactor (WP2.1). To overcome major limitations of new engine technologies, the control of ignition by active species injection could be useful. To assess the interest of that new approach, engine studies and studies of the associated chemistry through experimental and kinetic modelling is needed (WP2.2).

[1] M. Chaos, .F L. Dryer, Int. J. Chem. Kinet. 42 (2010) 143-150.