This paper describes the development and application of the 1D thermo-fluid dynamic research code GASDYN to the simulation of a Lamborghini 12 cylinder, V 60°, 6.2 L automotive S.I. engine. The model has been adopted to carry out an integrated simulation (thermodynamic, fluid dynamic and chemical) of the engine coupled to its intake and exhaust manifolds, in order to predict not only the wave motion in the ducts and its influence on the cylinder gas exchange process, but also the in-cylinder combustion process and the pollutant emission concentration along the exhaust system. The gas composition in the exhaust pipe system is dictated by the cylinder discharge process, after the calculation of the combustion via a thermodynamic multi-zone model, based on a “fractal geometry” approach.
Moreover, the research work has been focused on the simulation of pressure pulses transmission and reflection in the complex multi-pipe junctions encountered along the exhaust duct system of high-performance engines, considering the three-into-one and two-into-one pressure loss junctions of the Lamborghini V12 engine. The simulation code has been enhanced to model the pressure variations occurring across the multi-pipe junctions. An approach based on the Bassett-Winterbone model for the multi-pipe junction has been developed.
Calculated results concerning volumetric efficiency, brake torque, cylinder pressure, gas composition and pressure pulses in the intake and exhaust system have been compared with measured data with satisfactory results.