Fluid-dynamic Analysis of Motorbike Race Engine Injection System

The working conditions of all components of a competition engine are very hard: they must assure durability and reliability during a race where the running conditions changes very rapidly. The injection system of a competition engine must ensure a great amount of injected fuel and a great precision about control (timing and quantity) of the injected fuel. In this paper a simulated analysis of a competition engine injection system is shown. The engine was developed by the race team of Aprilia and it will be employed in 4 stroke racing application. The simulation model of the injection system was accurately validated by experimental data. The model was performed by a mono-dimensional and commercial code, which ensures a good reliability and fast calculation times. The model was performed during the engine development, so in the beginning of this activity only design data was used to realize the model. In the first step only experimental data performed on system components by their own manufacturers was used to calibrate the model then, when the engine was realized and tested on an experimental bench, the model was validated by dedicated experimental test performed on the injection system. The model was used to test several design solutions, in particular it was used during the design and the choice of the injectors, furthermore it was used to test several system configurations. This model is an interesting example of a modellistic approach and methodology that could be employed during the development of a new engine and its components of high specific power.