HT07 on the track at Formula SAE 2023

Engineering Summary

In the 2022-2023 season, HyTech Racing embarked on an exciting journey, transitioning to an all-wheel drive car that demanded significant changes to the vehicle architecture. Driven by our sophisticated vehicle simulation and an iterative approach, the team executed the design with utmost ambition and efficiency, pushing the boundaries of each critical requirement.

HT07 has a plethora of design improvements over its predecessors. The heart of our innovation lies in the new hub motor architecture, where a custom gearbox, crafted using cutting-edge simulation software, has yielded significant improvements to our acceleration performance.

One of our standout achievements was the seamless integration of the quad inverters and motors with the energy-dense accumulator, thanks to our novel cooling system. Moreover, through advanced composite structural simulation techniques, we successfully developed an aero package that is lighter, stiffer, and stronger.

The pursuit of performance extended beyond the vehicle's mechanics to optimize the driver's experience. An exhaustive ergonomic study and experimentally driven design iterations led us to provide our drivers with a seating and steering position that offers unmatched comfort while ensuring they are positioned at a low center of gravity for optimal performance.

The redesigned suspension system proved to be a game-changer, significantly enhancing the car's balance and maneuverability, enabling our drivers to confidently push the vehicle close to its theoretical limits. Tuning HT07 was a rigorous process, involving hundreds of hours of on-track testing. This allowed us to validate the structural components, fine-tune the suspension setup, test our new torque vectoring software, and validate the onboard cooling systems. With features like adjustable roll centers, configurable aero elements, and software control of powertrain parameters, our vehicle offers unparalleled on-track adaptability for achieving perfect balance and handling.

Results

HT07 was our fastest car by a long shot! It broke the North American acceleration record, came 1st in skid pad, 2nd in Autocross, and made it to the design finals for consecutive years. Despite not being able to compete in endurance (due to a damaged pedal sensor) the team still managed to place 10th overall in the 2023 FSAE Michigan Electric competition.

HT07 Vehicle Details

Vehicle Mass

• 430 lb / 195 kg (measured)

Vehicle Dimensions

• Wheelbase: 1535 mm
• Track Width: 1200 mm

Performance Envelope

• Longitudinal: 1.0g (measured)
• Lateral: 1.8g (measured)

Suspension

• Quad-push rod double wishbone

Powertrain

• 4x AMK A2370DD Motors, KW26-S5-FSE-4Q Inverter
• 20,000 RPM, 21 Nm, 33 kW Peak
• 76 mph top speed (simulated)

Accumulator

• 530 V, 6.3 kWh, 80 kW Peak
• Custom LCO Pouch Cells

Aero Elements

• Compound Curvature Carbon Fiber
• 3.19 - 3.71 CI*A (simulated)
• 0.97 - 1.23 Cd*A (simulated)

Sensor Suite

• 20 Custom Analog Sensors, 7 SPI Signals, 28 Inverter Monitored Signals

Battery Monitoring

• Custom LTC 6811 BMS with 126 Cell Voltages, 72 Temperatures

Gearbox

• 11.86:1 Reduction

HT06 on the Endurance Track at Formula SAE 2022

HT06 Took Third Place Overall at the 2022 Competition

Engineering Summary

In 2022, HyTech Racing focused efforts on building an extremely lightweight and reliable vehicle with a low center of gravity and high lateral acceleration at all parts of the circuit. This was accomplished through an iterative design process focusing on high-level performance metrics and designing to the limit of each critical requirement.

HT06 features many design improvements over its predecessors. A novel battery pack cooling design strategy enabled HyTech's most energy-dense and tightly packaged accumulator ever. Advanced composite structural simulation techniques led to the development of a lighter, stiffer, and stronger aero package. A complete ergonomic study and experimentally driven design iteration gave our drivers a comfortable seating and steering position while seating the driver in the lowest possible position to even further improve acceleration performance.

Tuning HT06 took place during hundreds of hours of on-track testing to validate structural components, dial-in suspension setup, test launch control software, and validate onboard cooling systems. An adjustable anti-roll bar, configurable aero elements, and software control of powertrain parameters allowed for quick on-track adjustment of vehicle balance and handling.

Results

HT06 placed 3rd overall out of 55 teams in the 2022 FSAE Michigan Electric competition. The team also received 2nd in cost, 3rd in acceleration, 3rd in skidpad, and 4th in design.

HT06 Vehicle Details

General

• Weight: 386 lb (175 kg) measured at Formula SAE

Chassis

• Steel tube space frame

Suspension

• Double unequal length wishbone
• Ohlins TTX25 dampers

Powertrain

• Chain sprocket reduction
• Clutch type limited slip differential

Electric Drive

• Motor: Emrax 207 Medium Voltage
• Inverter: Rinehart CM200DZ
• Battery: 84S1P LiCoO₂ pack with 5.6 kWh energy capacity
• Peak outputs: 80 kW
• Peak torque: 160 Nm

Aero Package

• 2 element front wing
• 3 element rear wing
• Coefficient of lift: -2.6
• Coefficient of drag: 1.4

Electrical Controls

• Low voltage controls: Teensy 4.0 Microcontrollers that run 6x faster than previous Microcontrollers
• High voltage controls: New team-built precharge and discharge controls circuitry. Clean-sheet object oriented BMS management system embedded software
• Data Acquisition: Created two new PCBs to interface with various sensors, revamped parser and live telemetry console.

HT05 on the Endurance Track at Formula SAE 2021

HT05 Took Second Place at the 2021 Competition

Engineering Summary

For the 2021 competition year, our team continued our iterative design approach building on the work that was unfortunately interrupted in 2020. We continued to apply our three design principles during our design of HT05: lightness, serviceability, and robustness.

Our weight only increased 20 lb (9 kg) compared to our 2019 vehicle, while also adding our first ever aero package.

HT05 was HyTech's first vehicle to implement an aerodynamic package, which consisted of carbon fiber composite front and rear wings. This package greatly improved the cornering performance of the car and with it skidpad and autocross times dropped significantly. The team also took a new, quantitative approach to tire selection, collecting experimental data on tire heating curves and comparing critical parameters such as tire rates, cornering coefficients, and max lateral force. With this data, the team settled on the stiffer Hoosier R25Bs to meet the demands of tight-cornered FSAE tracks.

Our team found many ways of increasing the robustness and reliability of the new design. We worked with our sponsors to rigorously test and validate every cell in our battery pack, allowing for better cell life models. We also continued to improve our assembly process and testing process for all boards, decreasing the failure rate and time spent overall. We also spent a large part of the year testing the vehicle on track, enabling optimal tuning of the vehicle setup and vehicle software well before comp.

Results

We won second place at Formula SAE Nevada, and had the fastest endurance lap overall. We were especially proud of successfully passing technical inspection in the 115°F competition conditions.

HT05 Vehicle Details

General

• Weight: 383 lb (174 kg) measured at Formula SAE

Chassis

• Steel tube space frame

Suspension

• Double unequal length wishbone
• Ohlins TTX25 dampers

Powertrain

• Chain sprocket reduction
• Clutch type limited slip differential

Electric Drive

• Motor: Emrax 207 Medium Voltage
• Inverter: Rinehart PM100DX
• Battery: 72S1P LiCoO₂ pack with 5.8 kWh energy capacity
• Peak outputs: 80 kW
• Peak torque: 160 Nm

Aero Package

• 3 element front wing
• 3 element rear wing
• Coefficient of lift: -2.084
• Coefficient of drag: 0.907

Electrical Controls

• Low voltage controls: Updated vehicle ECU and created custom dashboard PCB
• High voltage controls: Isolated BMS utilizing Analog Devices LTC6811 chips and custom management software
• Telemetry: Live vehicle data transmission and graphing using AWS

HT04 on the Endurance Track at Formula Hybrid 2019

HyTech's Car at the Finish Line

Engineering Summary

For the 2019 competition year, our team continued our iterative design approach. We applied three design principles during our design of HT04: lightness, serviceability, and robustness.

Our weight decreased 45 lb (20 kg) compared to our 2018 vehicle, with a noticeable weight reduction in each vehicle subsystem.

We greatly increased vehicle serviceability in a number of ways. We implemented an easy-to-install eccentric chain tensioning system as well as a drivetrain package that could be installed and removed from the vehicle without disassembling. Quick disconnect brake lines allowed us to remove the pedal box or corners without having to rebleed brake lines. Our high voltage battery pack redesign featured easily removable panels and a busbar layout that reduced disassembly and assembly time.

Our team found many ways of increasing the robustness and reliability of the new design. We designed a rigorous testing platform for our batteries, ensuring that each cell was reliable before assembling it in our high voltage pack. We retrofitted our new electrical system onto an old vehicle, allowing us to perform extensive testing early on in the development cycle. We also developed a new assembly process for our Battery Management System circuit boards, decreasing the failure rate and time spent on assembly.

Results

We won first place for the second year in a row at Formula Hybrid, placing first in the Design, Autocross, and Endurance events, and setting a record as the fastest electric team to ever finish the 44 km Endurance course. We also set our own personal record as this was the first competition where we successfully competed in every event.

HT04 Vehicle Details

General

• Weight: 368 lb (166 kg) measured at Formula Hybrid

Chassis

• Steel tube space frame

Suspension

• Double unequal length wishbone
• Ohlins TTX25 dampers

Powertrain

• Chain sprocket reduction
• Clutch type limited slip differential

Electric Drive

• Motor: Emrax 207 Medium Voltage
• Inverter: Rinehart PM100DX
• Battery: 72S1P LiCoO₂ pack with 5.8 kWh energy capacity
• Peak output: 80 kW
• Peak torque: 160 Nm

Electrical Controls

• Low voltage controls: Power distribution module, telemetry and data logging system, and vehicle ECU integrated onto single PCB
• High voltage controls: Isolated BMS utilizing Analog Devices LTC6804 chips and custom management software
• Telemetry: Live vehicle data transmission via cellular network as well as onboard logging