Simulation Support for Control Issues in the Context of Modern Diesel Air Path Systems

It is now obvious that the air path system will have to increase its performance to manage the in-cylinder conditions required by the combustion process if significant raw emission reduction is expected in Diesel engine applications. This crucial issue means air path evolutions with complex systems including advanced technologies such as Variable Valve Actuation (VVA) or two-stage turbocharging, and engine control capability improvement to optimise accurately the engine behaviour under transient conditions. At this stage of complexity, the engine controllability becomes a first-order factor to be taken into account in the technological orientations. Thanks to a high versatility of engine architecture, good physical trend capabilities and easy coupling with engine control, 0D simulation offers a very interesting support to help such investigations and discriminate the best Diesel air path system solutions. This paper describes how simulation is becoming a key tool to develop the control for various Diesel air path systems before having the corresponding experimental bench available, in order to anticipate the hard issues and begin to assess the controllability of each air path technology at the early stages of the engine development process.