Numerical Investigation on the Effects of the Setting of the Load Control System of a Formula SAE Single-Cylinder Turbocharged Engine on Fuel Efficiency and Performance

The target of motorsport has always been maximising the performance. Increasingly stringent rules on fuel usage, however, have moved the research on engine design and control rules toward efficiency enhancement. Turbocharging is a typical solution to match both targets; however, it suffers from the turbo-lag phenomenon, especially when the maximum power is limited by an air restrictor. In the present paper, an investigation on a combined solution aimed at contemporarily improving transient response and efficiency in FSAE events, both leading to a higher score, is carried out. In detail, the adoption of an anti-lag valve and an efficiency-based control schedule, markedly exploiting the wastegate actuator, is proposed in place of the classic combination blow-off valve and performance-based strategy. The analyses were carried out on the 520 cm3 single-cylinder 4-stroke turbocharged engine of the Firenze Race Team. In order to predict the potential of the proposed load control solution, a predictive combustion engine model (which design process is exhaustively described in the paper), adopting the K-k-ε turbulence model, was developed in the GT-Suite software and calibrated by means of test-bench data and 3-D CFD analyses. A vehicle model, calibrated by means of telemetry data, was finally developed to compare the proposed solution to the baseline load control system in typical race conditions, showing benefits in terms of performance, drivability, and efficiency.