E-Mobility Engineering 015 l EMotive Scarab off-road truck dossier l In Conversation: Giulio Ornella l Hall effect and magnetic sensors focus l Challenge of batteries for heavy-duty EVs l Alpha Motor Corporation digest l Automated charging insight l HVAC systems focus

into an application where there will be extreme cold or extreme heat then we would fit extra components to suit,” he says. The baseline system from Webasto provides thermal management for the battery, the motors and the cabin. It features a heat exchanger that can transfer energy between the water/ antifreeze loop and the refrigerant loop while allowing extra modules to be added to tailor the capacity to each application. “Giving the customer the ability to specify the vehicle to meet their budget is one of the biggest wins when it comes to making it affordable,” says Williams. “A key focus of ours is to get the bill of materials down to a very competitive level.” Refining maintainability Eliminating the IC engine, gearbox, transfer cases, propshafts, differentials and half-shafts means they are not there to break or wear out, and it also frees up a lot of volume under the chassis and consequently eases access to the other components. Williams points out, however, that it remains essential during the design process to review each component periodically for maintainability, characterising this as one of the biggest exercises the engineering team has to undertake. “It really starts with considering where the vehicle is going to be maintained, who is going to be maintaining it and what sort of tools they will have, and then designing relevant parts of the system to suit that,” he says. “Clearly, there are different tiers of maintainability and tasks that are likely to be carried out at the roadside or in the field with limited tools at a local depot or a fully equipped maintenance base. At its simplest, if you must access a bolt to remove a component, can you get a spanner on it?” Looking at the vehicle as it is now, without a body on the chassis (other than the cab), most of the working parts are easily visible, from the motors and hubs in the wheels to the suspension arms, the suspension air springs, dampers and inverters, all with clear space around them. In terms of electrical components though, there is still some work to be done, Williams notes. Here, maintenance access will have to be balanced against keeping parts out of harm’s way by, for example, ensuring they won’t snag on obstacles over which the vehicle passes. One of the biggest jobs, he notes, is re- routing the cables from the inboard- mounted inverters to the wheel motors through the centre of the suspension articulation. “We are coming up with a solution that will allow the cabling and all the other services such as hydraulic hoses and cooling pipes to sit centrally and move in relation to the wishbones so that they are all suspended and supported,” he says. “We have a protective casing for them as well, and routing them centrally allows us to accommodate the full articulation of the suspension and, if a customer chooses a steering axle, we won’t have wires biased to one side.” As operations manager, Josh Roles is responsible for procurement, working with suppliers to make sure the right materials and components arrive of inputs and outputs, and what we can then do with their controls,” he says. “Webasto have been great with technical support, doing everything they can to help us.” Staying cool Thermal management is another area in which EMotive is working with Webasto, which is helping to optimise the system for different customers and applications, and helping to determine what each user needs in their particular operating environment. “What we don’t want to do is throw everything at it and give them a really expensive system that just isn’t needed,” Williams says. “For example, we can harvest small amounts of power that would otherwise be wasted by the motors, the battery or the inverters and pump it back into the cab environment.” He explains that with a small cab seating three people, and operating in a temperate environment, only a modest amount of heating and cooling capacity is needed, while an adventure tourism vehicle with a cabin that holds 20 people will have much more demanding thermal management requirements. “Again, modularity will enable the vehicle to perform quite happily, for the sake of argument, from -10 C to + 35 C with a standard system, but if it is going The 48 V battery isolator switch is accessed through the top of the chassis. This is also how the battery is installed and removed, but that will change to side access for the production version (Author’s photo) 32 Autumn 2022 | E-Mobility Engineering