2015 Engine Team Thomas Carpenter, Jim Hoffmeister, Cyrus Jordan, Brian Phung, Lyndon Wixom, Vinh Nguyen
Advisor: Dr. Samuel Drake, Department of Mechanical Engineering
Engine Performance Data:
To benchmark the engine’s performance, a
chassis dynamometer was used. This method
for testing the powertrain provided
horsepower and torque figures from the rear
wheels. During testing, a peak horsepower of
41 [HP], and a peak torque of 34 [lb*ft] were
observed. These “dyno-graph” results may be
seen in the figure below. Project Description:
The University of Utah Formula SAE Engine Team was tasked with
providing an optimized engine/drivetrain system for the 2015 FSAE racecar. This included
providing a powerful and reliable powertrain capable of propelling the racecar in the 2015
FSAE competition. To do this the team took a KTM 525 ATV engine and performed several
modifications. Most notably, the engine was converted from carbureted to fuel injected,
and from naturally aspirated to turbocharged. These modifications were performed to
generate maximum power output given the limitations of a mandated intake airflow
restrictor. The team was able to overcome many obstacles to provide an optimized engine
package for the “Formula U” racecar.
1-D Gas Dynamic Engine Model
The given results were achieved by increasing
the engine’s displacement with a 570cc “big
bore kit,” tuning the fuel and ignition systems
using an AEM-EMS computer system, and
employing a Garrett turbocharger to provide
approximately 10 [psi] of intake boost
pressure. This empirical data closely resembles
the results of analysis obtained through
Ricardo Wave, a 1-D Gas Dynamic Modeling
Program. The model’s accuracy was validated
using the dynamometer testing results.
This complete engine system model was generated using the program Ricardo Wave. The results
of this model were used to determine the optimal engine displacement and compression ratio
when a rebuild of the combustion cylinder was necessary. This model was able to provide accurate
horsepower and torque figures regarding several different available engine configurations. The
results of this analysis directly led to the decision to use the 570cc “big bore kit” with a 12.5:1
compression ratio. This model also took into account the effect the FSAE mandated restrictor had
on the intake air-flow.
Engine Peripheral Optimization:
Great importance was given to refining integral
parts of the engine system through computer
modeling and analysis. Two examples of this
are provided below. ANSYS Fluent was utilized to aid in designing a
“venturi-style” intake restrictor. The optimal
geometry of the restrictor is an inlet and
outlet taper of 16° and 6° respectively.
A CFD model was used on the gas tank to
ensure “fuel starvation” never occurred. The
picture above shows a 1/8th full gas tank
subjected to a 2g turn. Packaging
Thanks to our Sponsors:
KTM 525 Engine
A very important consideration in vehicle
design is how operational components are
c o n fi g u r e d w i t h i n t h e c h a s s i s . M a n y
considerations were taken when the engine
system was implemented within the racecar.
These considerations helped to determine the
placement of all respective subsystems and
their components.