Development of a High Performance Engine for a Formula SAE Racer 2012-01-0833

The paper reviews the theoretical and experimental development of the engine powering the 2011 Formula SAE single seater of the University of Modena and Reggio Emilia (UNIMORE). The general design criteria followed by the UNIMORE team are discussed and compared to those chosen by other competitors. In particular, the reasons supporting the selection of the engine type (single cylinder by Husqvarna) are explained in details. The adoption of a single cylinder, instead of the more powerful four-in-line, required a much bigger effort for getting an acceptable level of brake power. Therefore, the development was massively supported by CFD simulation (both 1D and 3D) and by experiments. It was found that the most important design areas for the single cylinder are: the intake system, including the restrictor (20 mm), the intake runner and the plenum, and the muffler. GT-Power was the main CFD tool used in the project: after the experimental calibration of the base model, full load simulation have been carried out in order to optimize the engine geometric parameters, taking into account a number of constraints, decided by the team. The optimization goal was not just to have an engine as powerful as possible, but to find the best package of both engine and vehicle.

Besides full load steady calculations, also transient engine simulations during a car acceleration have been performed. Engine-out noise was monitored too, in particular at the testing conditions indicated by the competition rules.

Finally, a complete performance characterization of the optimized engine was predicted before starting the testing at the dynamometer bed. These performance maps helped to speed up the calibration process, and allowed the team also to get a rough estimation of the car fuel efficiency during the endurance event.