2019 Eta World Record Specifications
Eta, named for the Greek letter used to denote efficiency, was designed with a singular goal, to hold the title of “World’s Most Efficient Electric Vehicle”. Over the 2019 season, the aerodynamic shape of Maxwell was heavily optimized in both Altair AcuSolve and wind tunnel tests to produce an absolute minimum of air drag. The rest of the vehicle was similarly optimized, using a novel direct-drive motor and a featherweight carbon fiber monocoque. On June 23rd 2019, it successfully completed it’s goal, setting a new Guinness World Record!
Vehicle Weight: 20 kg race ready
Chassis: Carbon fiber monocoque with nomex honeycomb
Motor: Mitsuba M00512-IV
Drivetrain: Direct-drive
Electronics: Custom sensorless motor controller with tracking buck converter
Tires: Michelin 45/75R16
Measured CdA: 0.0328 m2
Measured peak motor efficiency: 88%
Nominal Power Consumption: 18.8 W at 15 mph
Result: 797 mi/kWh, 1283 km/kWh, 27,482 MPGe, Guinness World Record Achieved!
2018 Maxwell World Record Specifications
Over the summer of 2018, Maxwell was retrofitted with a hydrogen powertrain, and highly optimized for a world record attempt. Since the attempt would be on a better track near our school, we tested the car very rigorously beforehand. Based on a through analysis of the data, we could tune the vehicle to exactly this attempt. Extensive research went into optimizing the tire rolling resistance, fuel cell efficiency, and motor efficiency.
More details about the powertrain are available here. The preprint for our paper, describing the design tradeoffs in more detail is available here.
Vehicle Weight: 26 kg race ready
Motor: Koford 60LH175A
Electronics: Custom motor controller and telemetry system with auto-throttle
Fuel Cell: Horizon 100W with custom controller
Hydrogen Storage: Horizon metal-hydride
Load Levelling: 19V 170F supercapacitors
Nominal Motor Power: 75 W
Nominal Vehicle Power Loss: 21 W
Fuel Cell Efficiency (incl. auxiliaries): 58.4%
Motor Controller to Wheel Efficiency: 86%
Electric Efficiency: 723 mi/kWh, 1164 km/kWh
Result: 14,573 MPG, 6196 km/l, 1931 km/cu m, Guinness world record achieved!
2018 Gemini Specifications
After the molds for our newly designed body for 2018 were destroyed due to mistakes in layup, the team decided to continue pushing to compete with two prototypes in the Eco-Marathon for 2018. Additionally, the Shell-mandated hydrogen tank was massive, and wouldn't fit in Maxwell's body. With only a few weeks before competition, we dusted off the 2016 electric prototype, and modified it to compete in the hydrogen category. It was renamed Gemini to celebrate one of the pioneering applications of fuel cells: a power source for NASA's Project Gemini! It features a novel DC/DC converter to provide a constant load to the fuel cell despite fluctuating motor loads.
Category: Hydrogen prototype
Vehicle Weight: 35 kg race ready
Chassis: Carbon fiber monocoque with nomex honeycomb
Tires: Michelin 44-406
Electronics: Custom developed motor controller
Fuel Cell: 100W Horizon PEM fuel cell, custom controller and DC/DC converter
Motor: 350W hub motor
Result: 2018 Shell Eco-Marathon Americas - First Place Hydrogen Prototype
Official Score: 383.1 mi/cu m
2017-2018 Maxwell Eco-Marathon Specifications
Category: Battery-electric prototype
Vehicle Weight: 24 kg race ready
Chassis: Carbon fiber monocoque with nomex honeycomb
Track Width: 58 cm
Wheelbase: 126 cm
Tires: Michelin 45/75R16
Electronics: Custom motor controller and telemetry system
Motor: Brushless outrunner for model aircraft, 149kv
Nominal motor power: 250W
Drivetrain: Single stage chain reduction
Frontal Area: 0.35 sq m
Drag Coefficient: 0.10
2017 Result: Shell Eco-Marathon Americas - First Place Battery Electric, 296 mi/kWh
2018 Result: Shell Eco-Marathon Americas - First Place Battery Electric, 368 mi/kWh
Full Evolution of the Prototype Vehicle
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