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

and radiative or convective cooling from local interior structures. The HVAC control hardware developer expects HVAC blowers to remain common in EVs, because they are critical for driver comfort. He adds that systems are likely to feature multiple blowers to serve separate climate control zones more efficiently. The simulation expert also sees systems growing in complexity, as vehicle designers add more such climate control zones. Four-zone systems are already common, and he reports the implementation of five- and six-zone systems in larger Chinese vehicles, for example. Along with automated functions such as seat occupant detection and air quality sensing – the latter influencing whether the system switches to recirculation, for example – multi-zone systems will make even more demands on the control logic, he says. Another effect of the absence of an engine is that the HVAC and climate control system becomes a much more significant source of noise, vibration and harshness (NVH), impacting the design, location, installation methods and control logic of compressors, pumps, fans and valves, the engineering simulation expert says. Towards predictive control The automotive electrification specialists add that predictive control will be increasingly important for minimising energy consumption, predicated on a number of factors Focus | HVAC systems while being quicker to market than those that need a microprocessor and relieving the customer of the need to write any code. Where a microprocessor is available, it might be able to handle such drivers’ interaction with a CAN bus, although a system-on-chip device with all the required functions on a single piece of silicon can be a viable alternative, the expert says. Evolving comfort Continued development of HVAC and climate control systems in EVs is focused on meeting occupant comfort requirements while minimising energy consumption. The engineering simulation expert sees a lot of system designs during their evolution, and he believes heat pumps will grow in importance as the temperature ranges that are comfortable for the powertrain and the occupants come closer together than they ever could in IC-engined vehicles. There are limits to this convergence, however, as the HVAC, battery and charging systems expert points out. Modern battery cells ‘feel’ best at 25- 35 C, the electronics typically tolerate temperatures of up to 90-100 C, whereas HVAC systems need around 7 to 60 C. This is one of the key challenges inherent in closely integrated thermal management/HVAC systems. An efficient heat pump solution, the simulation specialist reckons, could potentially result in a 30-40% energy saving over a system based on PTC heaters, adding around 20-30% to the vehicle’s range. However, it is possible to end up with heavy, complex and expensive systems, so the ability to compare alternative designs virtually before any hardware is built is very important, he argues, for which the company provides benchmarking. Further savings can come from localised heating and cooling strategies within the cabin, the expert from the HVAC systems builder says. This involves targeting occupied seats and the space around them with, for example, internal heating or cooling of the seat and steering wheel, Some suppliers of HVAC systems Austria AVL +43 316 787 0 www.avl.com Italy STMicroelectronics +41 22 929 29 29 www.st.com France Valeo +33 1 49 45 32 32 www.valeo.com Germany Eberspächer +49 711 939 00 www.eberspaecher-climate.com Mahle +49 711 5010 www.mahle.com Webasto Thermo & Comfort SE +49 89 8 57 94 0 www.webasto-comfort.com South Korea Hanon Systems +82 4 2930 6114 www.hanonsystems.com USA Allegro Microsystems +1 508 854 5800 www.allegromicro.com BorgWarner +1 248 754 9200 www.borgwarner.com Gentherm +1 248 504 0500 www.gentherm.com ThermoAnalytics +1 906 482 9560 www.thermoanalytics.com Typical integrated thermal management and HVAC system component layout for an EV, showing the coolant and refrigerant loops (Courtesy of Webasto) 68 Autumn 2022 | E-Mobility Engineering