Pre-ignition phenomena in the tension field between operating agents and thermodynamic boundary conditions

Abstract

Against the background of EU legislation with regard to CO2 emissions, a development trend towards higher geometric compression is emerging for gasoline engines. In principle, this leads – especially in combination with high mean pressure at low engine speed – to a higher pre-ignition tendency, well known as low speed pre-ignition (LSPI). The worldwide use of engine families with different fuel and oil quality represents an additional challenge, which has to be ensured within the scope of series development. IAV has extensive expertise and methodical approaches to minimize the risk of pre-ignition starting in the preliminary development through to series application and to avoid engine damage in the field. The definition and phenomenology of pre-ignition are presented. The presentation highlighted thermodynamic aspects as well as influences from operating agents and engine design. By using the IAV enthalpy approach, it is possible to evaluate designed engines objectively. This knowledge can also be used in the development of new engines concepts. Finally, a test method is presented which is used for the final assurance of the operational stability even in the case of stochastically occurring pre-ignition.