As engineers, validation of our designs is one of the most vital stages of the design process. As with every section on our team, the Powertrain section have dozens of tuneable variables including manifold pressure, intake geometry, engine fuel and ignition parameters and exhaust geometry, all of which can have significant effect of the performance and reliability of our turbocharged, single cylinder KTM 500 engine.
To test and tune these factors, we make use of an engine dynamometer, more commonly known as a ‘dyno’. An engine dyno is a machine which is directly connected to the output shaft of our engine, as opposed to a ‘rolling road’ style dyno, where torque is measured from the rear wheels. Our dyno applies an opposing load to the running engine. By measuring the force required to resist the rotation of the engine, the torque being output by the engine at a given RPM can be calculated. Some simple calculations then allow us to calculate the power output of our engine. By running these tests across the full revolution range of our engine, we are able to obtain a power vs RPM curve. This is a very important visual tool for us to understand the power characteristics and response of the engine, where performance and smoothness are absolutely vital for our drivers when pushing to the limit on track.
From here we are able to begin the tuning process. Specially designed, variable intake and exhaust components are built including a plenum, intake runners, injector seats and headers. By making use of spacers and modular pieces, we are able to vary the effective volume, length and position of these components. These specially made parts allow us to iteratively measure the torque and power output as we modify their geometry and validate our calculations and simulations.
At the same time, we are able to modify our engine mapping through our Motec M400 ECU, which allows us to accurately monitor all aspects of our engine and make fine adjustments to fuelling and ignition timing to have a reliable powertrain package, while extracting every last kilowatt from our KTM engine. The results of this not only benefit the current year’s car, but also provide invaluable reference for future team members when it comes time to design new powertrain packages.
This ultimately benefits the team for numerous years, and ensures the transfer of vital knowledge, one of, if not the most important elements to a successful FSAE team.
– Daniel Crouch (Powertrain)