Design and develop a lightweight and powerful Formula Student Race Car
During my undergraduate course, I worked with the formula student team in our college. We designed a new vehicle which was more efficient, lighter and had a faster acceleration time than its previous iterations. We designed a new intake system and reduced the weight of the final drivetrain along with the differentials. We also fabricated all the components in-house along with the complete assembly. We also designed custom ECU maps to suit our configuration. We entered into various races and competitions and were victorious in most cases with an envious win record and trophy cabinet
Project duration
August 2013 - June 2016
Role
Head of Operations and Finance, Powertrain team member
Relevant skills
CATIA V5, Ansys, Altair Hypermesh, fabrication, vehicle data logging, dynamometer tuning
Team members.
THR teams 2014 - 16, Dr Rajesh N Mathivanan, Dr Krishna V, Dr Sridhar K S
Understanding the problem
Design a Formula student race car with the following objectives:
Weight Reduction
Easy debugging of the electronics and powertrain systems
Extensive testing and validation for all the components to enhance reliability and improve the performance
Complete construction from idea to testing should be done in-house
The Solution
As the various departments worked towards achieving this goal, we as the powertrain team decided to use a newly designed intake plenum which would be vital to the vehicle’s performance and designing an innovative drivetrain system to reduce the weight especially in terms of rotating mass. Advanced materials would be used to improve on the structural strength. The rear cockpit would be designed to keep the center of gravity(CG) low. The stock wiring harness of the powertrain would be changed to a new harness using a custom electronic control unit(ECU). The ECU’s would be programmed with multiple engine mappings to aid the driver.
I was also responsible for the operations of the team and organized multiple testing sessions at strategic points along the build of the car. All procurement of components was done ahead of time by using a centralized inventory system designed by us. Having hard deadlines for the individual teams helped in completing the car well ahead of time and run comprehensive tests.
The Design
Intake System
Intake system was designed to enhance engine breathing capacity. system (except for the throttle body) was machined using aluminum to eliminate air leakage and subsequent surging which was encountered previously. The plenum volume was chosen to be 2.5ltr which is around 6 times engine displacement, along with a runner length of 200 mm. We see that the pressure loss is minimal using this configuration.
The fuel tank was designed to be placed behind the driver’s seat and was designed to have a volume of 4.5ltr along with a long filler neck away from the engine and other hot parts. The differential was redesigned to save weight from the OEM road car differential. It was designed to have a much lighter case along with a custom sprocket which helped with the performance of the car. The differential was mounted inboard along the same load line as the engine. Overall we see a 20% reduction in total weight of the powertrain parts along with the engine
Anlysis of the designs
Intake System
CFD analysis of the the intake system was conducted using the SST turbulence model as it predicted reasonably accurate values The idea is to increase the volumetric efficiency of the diffuser by reducing the Turbulence kinetic energy, we found an error of 5.5% between the ideal mass flow rate and the CFD mass flow rate. The optimized design showed the least pressure drop.
Analysis of drivetrain components
FEA analysis was conducted on the various transmission components like the differential mounts, chain tensioner, sprocket. The differential used was an OEM automobile open differential
Fabrication and assembly
The major portion of the parts were fabricated by the team in house. The drive train parts along with wheel hubs and suspension control arms were fabricated using Aluminum 7075 series for added strength and light weight. The body panels were made using light weight composites. The chassis structure was constructed using AISI 1018 for its advantages in cost, availability and lack of post welding heat treatment.
