Bradley University Formula SAE - Powertrain Team

The vehicle is powered by a Honda CBR600RR four cylinder 599cc engine. This engine is naturally aspirated with a 12.2:1 compression ratio. The engine will operate on 100 octane gasoline. The max power and max torque design engine speeds are targeted at 11500 RPM and 10500 RPM, respectively. The direct fuel injection system has an operating pressure of 42 psi with injectors located at the top of the intake plenum over the runners mounted at a 50° angle just before the inlet into the engine.

 

The intake manifold is student-designed and incorporates a 20mm restrictor as specified by the 2012 Formula SAE Rules. The intake has an approximate plenum volume of 2982 cc and is constructed from aluminum. The runners from the plenum to the engine are 185 mm in length made from abs plastic. Exhaust gases exit the engine through four equal length runners and gather into one 2.4 inch collector.

 

The fuel/air mixture is ignited by a digitally controlled ignition system. The engine control unit used is a Power Commander V, with live measurements displayed on an LCD screen.  The ignition timing is controlled by the Power Commander V software and is dependent on engine speed and throttle position.

 

Power is delivered to the rear wheels via a continuously variable transmission (CVT). The use of a CVT is design constraint imposed by the Bradley University client.  The use of a CVT eliminates the need for precise shifts, resulting in higher and smoother acceleration when the car is controlled by inexperienced drivers.  This also allows for the engine to operate at a speed which produces maximum power, leaving the speed of the car to be controlled by the CVT alone.  In order to mate the CVT to the engine, an output housing was designed to replace the stock transmission cover. This piece is machined from a solid block of 6061 T6 Aluminum. It houses the bearing for the output shaft, the holes for the starter gear, and space for the crank angle sensor. The engine was FARO laser scanned in order to ensure that the shafts were concentric to the engine housing and that there would not be any interference from any of the critical components housed in the previous cover. The stock reduction gear of the engine is utilized and keyed to the shaft in order to keep the oil pump drive system intact. The final drive ratio is four, with a vehicle top speed of approximately 83 mph.

 

The team used Pro/Engineer Mechanica to perform FEA analysis on all shafts used to transmit power, with results validated through hand calculations. The intake and exhausts manifolds are analyzed with flow packages in Lotus Engine Simulation. The engine was flow tested to develop a more accurate design for the intake manifold. Dynamometer testing of the engine is necessary to make final fuel and ignition adjustments. It is also necessary to perform a final tune of the CVT on a dynamometer.

This year the Team is composed of:
Devin Norton (Team Captain)
Alex Boen
Steve Schwartz
Dan Walker