BMW C evolution

BMW Motorrad has unveiled “a near-production prototype” of an e-scooter, conceived as “a future-oriented vehicle for commuting between the urban periphery and the city centre”.

The so-called C evolution follows on from the concept E-scooter released in 2011, and then a design study shortly thereafter dubbed BMW Concept e.

BMW Motorrad concentrated on two major pillars for the C evolution: performance to that of a maxi scooter with a combustion engine, and a long range in realistic conditions of use. Here’s what the company has come up with:

In terms of acceleration from 0-60km/h, BMW Motorrad claims it comfortably holds its own against current maxi scooters a capacity of 600cc or more.

The C evolution uses the same lithium-ion storage modules as are installed in the BMW i3.

The heat of the high-voltage battery is dissipated by means of an aerodynamically optimised cooling air shaft at the centre of the battery casing through which there is a constant flow of air. To ensure optimum heat dissipation, the battery base has longitudinally arranged cooling ribs.

However, the battery casing in die-cast aluminium not only holds the cells with their special architecture but also the entire electronics unit for monitoring the cells. It also acts as a load-bearing chassis element.
The C evolution is powered via a drivetrain swingarm, with the alternator positioned behind the battery casing and integrated in the swingarm.

The secondary drive is via a tooth belt from the alternator to the rear belt pulley on the output shaft. From here, power is transferred to the rear wheel via a planetary gear. The total gear reduction is 1:8.4, while the maximum rotational speed of the alternator is 10,000rpm.

The alternator and power electronics are liquid-cooled.
Energy recuperation commences when the throttle grip is closed, and is also carried out during braking, converting kinetic energy to electrical energy so as to charge the battery.

The battery is charged at a regular household socket or a charging station. When the battery is completely flat, charging time ideally lasts less than three hours.

Chassis design is based on a hybrid composite structure made up of a load-bearing, torsionally rigid battery case made of cast light alloy with integrated mounting for the single-sided drivetrain swing arm. Bolted onto this are the steering head support and the rear frame in steel tubing.

Suspension consists of a 40mm upside-down fork, and the rear is a single-sided drivetrain swingarm with a spring on the left-hand side for damping. Travel is 115mm front and rear. The C evolution rolls on a five-spoke light alloy, 15-inch die-cast wheels.

The instrument panel has a large TFT display, and includes a battery charge state (SOC = State of Charge) and the energy balance. The latter is displayed by means of a progress bar, indicating to the rider whether energy is currently being converted into forward propulsion or being recuperated.
Colours are white or green.