The Drivetrain: A new direction

It is important for a racecar to have a powerful and lightweight motor, but just as important to assure the power from the motor is delivered to the tires by a lightweight and efficient system: the drivetrain.

Why electric racing?

One could ask why we at Vermilion racing chose an electric car as opposed to a combustion car for racing.

There are two answers:
We live in a world where global warming is a reality. According to WHO, 27% of the worlds CO2 emissions in 2010 was from transportation. Even though cars only is responsible for a fraction, exhaust particles from combustion cars help cause an estimated 3.7 million premature death annually. It is clear we need to combat this trend.
The other answer, that is the focus of this article, is the racing advantage.
A combustion engine’s rpm has to be managed. If a combustion car comes to a complete stop, the engine would stall if not for the clutch and if the rpm’s become too high, the engine looses power, and we have to change gear. An electric motor has an almost linear power curve and instant peak torque. Peak torque is a major reason as to why LMP1 and F1 cars have small electric engines for acceleration out of corners.

This means we can do away with the clutch, clutch pedal, and gearbox. Thereby saving weight and reducing the number of moving parts in the drivetrain. 

In addition, combustion cars operate on small explosions in every cylinder. This means the power delivered to the drivetrain include violent peaks from every combustion. In other words, it is not guarantied a drivetrain for a 80 kW electric motor can survive a 80 kW combustion engine. 

The main disadvantage is the large and heavy battery. However, since everything is connected by wires and not gears, the battery can be moved and placed low and centered in the car for greater cornering. 

The design

Because of the advantages of the electric motor, the drivetrain is both small and lightweight. An axle mounted directly to the motor drives a small sprocket, which in turn drives the large sprocket mounted to the differential which drives the rear wheels of the car.

• Emrax 228 motor delivering max 240 Nm and 80 kW (107 hp)
• Differential: Drexler LSD 
• Chain: 428 motorcycle chain
• Gearing: Fixed 3.4:1
• Weight: 15 kg
• Size: 250x450x250 mm
• Materials: 6082 and C45

Production has already started, and more parts of the car will soon follow so stay tuned!

Thank you for your support.

Nicolai Boertmann

SOURCES:

https://www.911chips.com/dyno.html 

http://emrax.com/wp-content/uploads/2017/01/emrax_228_technical_data_4.5.pdf 

https://www.who.int/sustainable-development/transport/health-risks/climate-impacts/en/