From S1 to S4: The Evolution of the Powertrain
Posted on: 05 September, 2018
From Season 1 to Season 4, the evolution of technology in Formula E – the world’s first all-electric racing series – has been rapid. Hence, it’s of utmost importance that we are on top of our game when it comes to possessing technical prowess.
Speaking of technical prowess, it is safe to say that the tech team behind the powertrain for the M4Electro held its own in Season 4 of Formula E.
The Inverter is an integral part of the Powertrain. You might ask what does it do? Well, it is the electronic unit that transfers electricity from the battery to the motor and back again.
In Season 1, all teams had to use a standard Formula E-specified inverter, made by McLaren Applied Technology. Fast forward to Season 4 where teams can specify our own inverters.
Our Season 4 inverter was manufactured by Magnetti Marelli with the following specifications:
- Silicon Carbide switching
- Twin unit in one casing for six-phase motor
- Mounted inside rear carbon casing
- 8KG lighter than Season 1
The Inverter is the electronic unit that transfers electricity from the battery to the motor and back again.
It's well known that modern motors are far more efficient than electric motors even from a few years ago. Especially when you consider the size and weight of modern motors.
We've moved from a standard Formula E specification in Season 1 to a Magneti Marelli six-phase unit in Season 4. The motor in the M4Electro was 1KG lighter than the one used three seasons earlier, with a maximum speed of over 20,000 rpm and maximum torque of more than 200Nm.
The positioning of the motor in the race car has also changed over the years. While it was longitudinally mounted back in Season 1, it's now mounted transversely for more efficient driveline.
In Formula E, the race car often needs multiple gears to have the motor in the right RPM range to be efficient.
Just like the inverter and the motor, in the inaugural season of the series, there was a standard Formula E specification for the gearbox too.
Zoom ahead to the season just gone by where the M4Electro had a Mahindra-specified reduction gearbox with one fixed speed, no gear shifts, and no bevel gear for greater efficiency.
DC TO DC CONVERTER
The DC to DC Converter effectively acts as a high-efficiency transformer.
From being part of the inverter in Season 1, it is now a separate unit, supplied under Mahindra specifications. It is important to note that not all manufacturers use a DC to DC converter.
Results? Improved efficiency from 84% to 90% and mass reduction of 30kgs, leading the car to mount a challenge for the championship.
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