E-Mobility Engineering 016 l Aurora Powertrains eSled dossier l In Conversation: Thomas de Lange l Automated manufacturing focus l Torque sensing insight l Battery Show Europe 2022 report l Sodium batteries insight l User interfaces focus

very efficient way, with good throttle response and minimum current losses or programming errors.” Interfacing and connectivity The driver’s control interface is a 7 in HD, high-contrast widescreen with control buttons on the handlebars, as touchscreens would be of little use in the Arctic cold, where hands should be gloved at all times and kept on the handlebars to maintain driver safety. One advantage of keeping all the vehicle controls on the handlebars, and a key advantage of the lack of a conventional IC engine and mechanical systems, is that the eSled is extremely easy to control. As the throttle is an electronic system, it has been programmed to respond precisely, quickly and intuitively to driver input, with even first-time operators finding it takes little time to learn how to use the system. The proprietary instrument cluster has been programmed in C, C++ and Qt, with data on parameters such as speed, estimated range and charge displayed on the screen as the driver chooses. 4G LTE receivers and antennas are installed to enable over-the-air software updates and notifications from the resorts or their tour guides. Although the team tested a range of motor types, including radial flux and DC motors, the final choice was heavily influenced by the constraint on available space inside the snowmobile’s chassis – everything must in effect fit between the legs of an adult person. Naturally, the ‘pancake motor’ configuration made for the narrowest possible power source without needing a gearing system between the motor shaft and the track sprocket. “Of course, the axial flux machine has a much bigger diameter than other types, but you can see from a side-on view that we actually have plenty of space for the diameter of our motor, just not so much for its length in the shaft plane,” Haavikko says. “No radial flux system would have allowed the compactness of the electric powertrain that we’ve achieved.” Autioniemi adds that, as new as electrified snowmobiles are, snowmobiles in general are widely considered a powersport vehicle, so they must still integrate a power unit that is as high in power and low in weight as possible. As such, the eSled’s integrated motor-inverter drive system weighs roughly 25 kg (including its external cabling and mounting parts) and occupies just 270 mm of diameter between the rider’s knees. It produces up to 60 kW of power, up to 140 Nm of torque, and has a top rotational speed of 7500 rpm. “We went for a single-unit motor- inverter package specifically to minimise the amount of space it takes up, and also to save on space and parts count in terms of things such as three-phase cabling and shared cooling pipes between the motor and inverter,” Autioniemi says. “It also guaranteed that the inverter would be scaled correctly for the motor, and that it would be able to control that specific motor in a “The telemetry unit in the eSled also has two-way transmission, so in tandem with the GPS system we’re including, drivers can see where they are on the trails, and tour leaders can keep an eye on where their guests are going, and prevent anyone from veering off-course,” Autioniemi adds. “Fleet owners can also keep track of their eSleds and tour guests this way, not just to make sure they don’t go missing but also to monitor subsystem performance and health for efficient maintenance.” Future plans Following the pilot trial programme for the new eSled’s priority beta test partners later this year, Aurora Powertrains plans to raise additional capital to fund its plans to scale up towards mass production, given not only the size of the market it is catering for, but several related markets for which it has begun accepting engineering requests. “Our battery modules and BMSs are to be used in a couple of different applications, with a few new customers and their products,” Autioniemi comments. “We’ve had enough interest that we want to enter serial production and commercialisation of not just our EVs but our batteries and VCCUs as soon as possible.” Although these applications cannot be disclosed in detail, the company points towards areas where EVs must be capable of working off-road in freezing, snowy conditions. They range from light snow ploughs and loaders to enormous tracked and articulated industrial utility machines for clearing snow, search & rescue, resource exploration, construction and other jobs. All these applications need highly reliable all-electric powertrains, tested and proven to keep working through hundreds of hours of Arctic conditions. ;Oe Åeet management software enaIles tracking of e:leds and tour guests via .7: as well as suIsystem OealtO and maintenance reXuirements via . 3;, Winter 2022 | E-Mobility Engineering 33 Dossier | Aurora Powertrains eSled