The paper reviews some of the areas in which the application of computational fluid dynamics (or multidimensional modelling) to engine flows is making an impact. Specifically it focusses on the current efforts at AVL on how to use these methods in the design and development process of high speed direct injection diesel engines. The underlying theoretical framework and some of the considerations pertaining to setting up multidimensional flow calculations are discussed. Results from typical flow calculations, obtained with a computer program system already in wide use within the automotive industry, are presented. These include 2- and 3-dimensional intake generated and compression induced flows within engine cylinders, flows inside an inlet manifold and the flow inside a super-charging device.The results reveal that the most important aspect of all these calculations is their capability for affording a more in-depth understanding of the complex physical phenomena under investigation. Additionally these methods can provide information which would be very difficult or impossible to obtain experimentally.It is demonstrated that multidimensional modelling can be incorporated either within the design process to assess alternative concepts, or within the engine development phase via performing repeated computations with different boundary and operating conditions to reveal common characteristics and trends.