The team has largely used standard, elastomer marine-mounting pieces for the other powertrain modules. After taking these various damping measures, the prototype boat was brought back to the lake and retested to gather fresh acceleration measurements. The end result was that the g-loads were found to be much more tolerable for the powertrain parts. On top of that, tests to investigate how the boat would handle unsafe usage included travelling to Lake Garda (in northern Italy) and using a ferry to generate large waves, which the eFantom was then steered to jump over. Vaulting the waves behind the ferry imparted heavy, bumpy impacts under the eFantom’s hull, which was fitted internally with motion sensors and associated cabling to measure shock, vibration, noise and other parameters. Further testing validated compliance with marine regulations on the survivability of every powertrain module against salt spray and similar ambient threats. Final validations of the eFantom are under way as of writing, with a view towards sales later this year. Cool controls The eFantom’s powertrain control system is built with a distributed architecture and assembled around a central ECU made from a blank sheet in-house at Porsche (including both hardware and software) to satisfy the company’s targets for automotive buses, including CAN, FlexRay and Ethernet to a degree of security deemed necessary for modern, connected vehicles. It also accommodates the necessary conversion modules (as well as digital and analogue interfaces) for dealing with naval communication protocols such as NMEA 2000. Additionally, from the Porsche side, two of the next-gen Macan’s high-performance computing ECUs have been incorporated (the Macan powertrain typically has five). These ECUs include energy management, charging and electrical safety contactor mechanisms to ensure the boat systems operate with consistent logic and safety, as in the Macan. The first one that the team carried over into the eFantom is responsible for the management of high-voltage systems. It connects directly to the Integrated Power Box (IPB), where the onboard charger is situated, and to a dedicated control unit for the charging sockets. The other ECU provides intelligent functions such as enabling customers to communicate with the boat using a key (eFantom users get a similar electronic key to Macan users), and an immobiliser function in the inverter to control starting and stopping using the key. These two ECUs, along with the central ECU and some additional lower-level controls, are housed in an enclosure that was designed and created for this project, given marine regulations on protection against the ingress of fresh and salt water, and the fact that the ECU enclosure in the Porsche Macan is designed for a dry environment (whereas the boat’s powertrain compartment will always contain some water). The team refers to the central ECU as its ‘eVCU’, and it is in essence the main connecting part between the boat’s sensory inputs and all of the outputs for controlling the various powertrain subsystems, such as signalling torque values for the inverter to execute. To do that it houses new software modules, including one that converts the throttlelever CAN into an automotive bus protocol, as well as safety modules for monitoring health and performance values at different component levels. The main protocol in the eVCU is a form of CAN, similar to that found in commercial EVs, with some modifications to have power and communications running within wiring harnesses simultaneously, and to meet regulatory requirements on the minimum thickness levels of marine cables (inside the ECU box are relatively thin automotive cables, while outside are generally much larger marine connectors and cables). The controls enclosure contains various ECUs from Porsche, running on a CAN bus similar in form to that in commercial EVs 22 March/April 2024 | E-Mobility Engineering
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