The 2007 FSAE (Formula Society of Automotive Engineers) engine systems design was based on the 2006 engine systems, which was the first turbocharged engine system used by UQ racing. The 2006 turbocharged engine systems produced a large increase in peak torque (25% over 2004), which occurred much lower in the rpm range. Although the peak power and torque plots are impressive, they came at the cost of engine response and weight. Slower engine response made the car extremely taxing to drive around the tight winding track used in Australasian FSAE competition, the drivers often complaining about the way the engine responded to throttle inputs and the drivability of the torque curve.
This report outlines the modelling, analysis and subsequent recommended modifications/redesigns of a turbocharged engine system for FSAE application.
During the feasibility analysis of a turbocharged engine system, it was found that turbocharging results in an economical improvement in vehicle performance over a naturally aspirated configuration.
The modelling of compact cross flow heat exchangers negated the use of intercoolers in FSAE application, showing that they had little effect on inlet flow density but caused significant delays in throttle response. As such the intercooler has been removed from this years design.
Inlet system analysis showed that the intercooler made up 80% of the total inlet system volume. Mass flow rates were found to be 30% below theoretical for a 20mm throat. Tuned length runners were shown to be insignificant when resonance tuning supercharge was not observed in dynometer data.
The exhaust system was redesigned using pulse converted junctions in a compact manifold configuration. An absorptive silencer is recommended due to the reduced backpressure on the turbine and the minimal silencing requirement due to significant noise damping from the turbine.
The code and analysis performed in this report will aid future FSAE team members in the design of turbocharged manifolds and heat exchanger sizing.
Overall the modelling and analysis were successful, resulting in improvement of several engine component designs. The key objectives of throttle response, weight and drivability were met theoretically, and the engine systems should perform significantly better than the previous