OEM & Lieferant Ausgabe 1/2022

93 all functions – from acceleration to onboard infotainment – from the same energy source. It is therefore essential for electromobility to make the thermal management systems in the vehicle as efficient and “intelligent” as possible in order to maximize the range actually available. In addition to this topic, another phenomenon can be observed in recent years: Partly due to the growing e-mobility start-up scene, competition within the automotive industry is rising rapidly. In order to increase competitiveness, developers and customers alike are placing more and more emphasis on climate comfort in the vehicle interior, particularly in the Asian market, but recently also in Europe and the USA. Last but not least, autonomous driving will revolutionize previous air-conditioning concepts, with occupants sitting facing each other instead of facing forward, for example, resulting in the need for a completely different distribution of air flows in the passenger compartment. For these reasons, it is necessary to develop a virtualization strategy in order to be able to map and optimize new thermal management concepts much faster and better at the same time. More efficient development processes thanks to virtualization To a certain extent, virtualization has long since found its way into thermal management development. Nevertheless, a large part of the comprehensive fine-tuning of the interior climate control still depends on the individual sensibilities of the application engineers involved, who have so far only been able to rely on objective measurement results to a very limited extent when evaluating comfort. The application tests required for this purpose currently not only provide mainly subjective results, they can also only take place late in the development process, since large parts of the hardware and software must already have been defined and integrated. In addition, these tests involve running numerous load scenarios in different climatic environments. For this purpose, elaborate test trips are made to sometimes distant locations such as South Africa or Death Valley with test vehicles and personnel, which is lengthy and cost-intensive. In order to be able to meet market demands for a high level of comfort in the vehicle in the future from an economic point of view, a development process for air conditioning and climate comfort is therefore necessary which – instead of being based on classic test drives – is primarily based on dynamic models and simulations. In this way, expensive application work is to be reduced to a minimum in the long term and largely replaced by fully transient calculations. The specialists at ARRK Engineering have designed a general development process that takes into account the individual steps of climate comfort development: starting with benchmark studies, through the design of the circuits and the functional and comfort design of the cabin air conditioning with development of the climate control strategy, to optimization and validation. The focus of the current work on the process is on the question of which prerequisites must be created overall in order to be able to implement the desired virtualization, and which elements must be worked out in more detail in the simulation. Air and heat dynamics in the passenger compartment To close the gaps that still exist, ARRK engineers are currently in the process of developing different models to represent all the factors involved. This includes, for example, modeling the HVAC component, which is the core component for controlling the air conditioning and air distribution in the vehicle cabin. The focus here is on the one hand on mapping the thermal behavior of the HVAC to transiently determine the inlet and outlet temperatures of the cabin air on the simulation model. On the other hand, the focus is on mapping the hydraulic behavior of the HVAC in order to obtain a statement about the air distribution in the individual ducts as a function of the individual flap positions in the HVAC and thus to be able to map the air distribution in the vehicle interior. In order to determine the information required for this, Image: © ARRK Engineering GmbH, ANAID studio/Shutterstock Image: © ARRK Engineering GmbH The ARRK dummy is equipped with 31 sensors evenly distributed over the body to measure air temperature and humidity, long-wave and shortwave radiation, and wind speed. ARRK Engineering specialists have designed a general development process that breaks down the individual steps of climate comfort development: starting with benchmark studies, through circuit design and functional and comfort design of the cabin air conditioning system with development of the climate control strategy, to optimization and validation.

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