Energica brought to the test of the MotoE in Jerez some important innovations to reduce the weight of the bike by 15kg; the main ones are the new motor and the inverter. In this post we make a first analysis of these two new components.
The weight of the MotoE has always been her Achilles heel and is the aspect that was immediately identified as the one to work on by Dorna and Energica. Introducing technical innovations in a new category is not easy, even more if a pandemic ends up in the middle. This is how the new engine for the MotoE, already ready to be mounted on the Ego Corsa last year, had to wait a year for the first laps on track.
The first feature of this engine is its weight, 10kg less than the previous model. Some weight was also gained by the new inverter thus bringing the MotoE 2022 to 247kg, about 15kg less than the previous model.
The advantages of the new engine are not only measured in lower weight but also in a different distribution of masses, less inertia and better handling, giving a completely new riding feeling to the bike.
All these improvements are the result of a completely new motor in concept and design. The motor of the MotoE of the previous three seasons was of the permanent magnet synchronous type (PMSM - Permanent Magnet Synchronous Motor). In that type of motor, the flow of alternating current that passes through the stator windings generates a magnetic field that drags the permanent magnets mounted on the rotor shaft. The latter transmits the motion to the pinion and from there to the rear wheel.
The new 2022 motor, on the other hand, is synchronous reluctance type (SynRM - Synchronous Reluctance Motor) and is based on a completely different operating principle. The SynRM type motor works on a very elegant principle that has been known for a long time, but only with the recent development of sophisticated control systems has it been possible to take full advantage of this extremely efficient electrical technology.
In a SynRM motor, the rotor is designed to produce the smallest possible magnetic reluctance (the resistance to flux of a magnetic field) in one direction and the highest reluctance in the perpendicular direction. The control system directs the magnetic field of the stator, so that it "rotates" around the rotor, generating a torque that rotates the rotor at the same frequency as the magnetic field of the stator.
The average torque of the SynRM motor is due to the rotor anisotropy obtained by means of a large number of flow barriers (air gaps). Small permanent magnets are inserted into the flux barriers for an increase in main torque density and power factor.
Without the permanent magnets of its predecessor, the new motor of the MotoE has less electrical losses and is more efficient, especially at high speed. Always for the same reason, the operating temperatures of the stator windings are lower as well as those of the shaft bearings. All of this has a positive impact on the overall efficiency of the new Energica powertrain.
The previous permanent magnet powertrain guaranteed a peak efficiency of 95%, which, combined with that of the inverter (92%), brought the overall efficiency of the system to 87%. The new 2022 engine features 97% peak efficiency as well as having a wider high efficiency operating range. The efficiency of the new inverter is 97%, thus bringing the overall efficiency to 94%, seven percentage points more than the previous propulsion system. The power and maximum torque of the new 2022 engine are the same, while the maximum rotational speed is higher, allowing the MotoE to increase top speed.
The front water radiator is used to cool the inverter, through a plate exchanger, and the motor stator. The rotor, on the other hand, is air-cooled: fans mounted at the two ends of the motor shaft convey the hot air inside the motor towards the side covers and from here the heat is dissipated into the external environment.
In the next days we will publish more details on the tech news of the MotoE 2022 along with the impressions of the riders.
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