Maximum Comfort from Minimal Control Input

For the one individual, it is too hot. For the other it is just right. And when a breath of fresh air is very welcome for one person, another complains about a draft. One thing is certain: comfort is a very personal thing, and also depends on how the individual feels on a given day. High time, therefore, to take a closer look at this subject and develop new solutions – such as a new concept for operating the air-conditioning and a smart, innovative comfort control system that is still available after changing a vehicle.

Today, air-conditioning control merely takes account of the passenger compartment’s mean temperature which, however, is only one of several factors that go into assessing comfort. “Apart from this, humidity and airflow as well as activity and clothing also play a key part”, explains Dr. Christine Junior, Technical Consultant for Thermodynamic Systems at IAV. “This is why we need a climate control system that includes these parameters if we want to bring about any noticeable improvement in the thermal comfort of vehicle occupants.”

IAV is working on a new approach for controlling climate in the passenger compartment that not only allows for temperature but these other factors too. It involves a new user interface: “Because of the many hard and soft keys and the various setting options, controlling the air-conditioning system isn’t always intuitive”, says Jan Ackermann, Senior Vice President for Energy and Concepts at IAV. “Sometimes you can only get the level of comfort you want by carrying out a whole series of control operations, if you can get it at all.”

To reduce this effort and largely rule out incorrect settings, IAV uses a completely different control concept that no longer requires any understanding of the air-conditioning system and involves less user input. Instead of pressing a lot of buttons, all the driver needs to do is use a finger to move a symbolic face on the infotainment system’s touch screen to tell the air-conditioning system how he or she feels – for example, upwards if it is too hot, or to the right if it is too drafty. The further the user moves it from the mid-point, the unhappier the emoticon looks – the distance from the center is the measure of dissatisfaction with the current situation.

The user can even tell the intuitive system which region of the body (head, torso or legs) the input relates to. This turns today’s control philosophy upside down: individuals no longer tell the air-conditioning what they want but simply describe the way they currently feel. The control system then has the task of enhancing comfort by adjusting temperature and airflow at the various air vents.

The aim is for the control system to adjust to the individual passenger with ever greater precision. “In the learning phase, the user needs to tell the system how he or she is feeling through the new user interface”, Dr. Junior says. “Later on, it knows what a person wants and can automatically adjust to individual preferences. This personal profile can, for example, be saved on a smartphone, immediately making it available after changing from one vehicle to another.”

But that is not all the new climate control system can do. Besides taking account of individual preferences, it will also include information from other sources – such as an appointment diary in the cloud – to prepare for the weather at the point of destination. Even the individual’s current mood is not left unnoticed: The system tracks his or her activity level (based on control interventions in the vehicle or through wearables), even recognizes whether a person is wearing thick or thin clothing, and allows for this in controlling occupant comfort. And all of this individually tailored for up to four climate zones per vehicle.

“In vehicle air-conditioning, the thermal comfort of occupants is gaining more and more significance”, says Ackermann, summarizing. “Our new operating concept and the control system based on computed thermal comfort come with the advantage that existing air-con actuators can be controlled more selectively, enabling the control system to provide thermal comfort more reliably than a conventional temperature control system can. In the bestcase scenario, this means that the user will not have to touch the climate control system any more, ultimately leading to greater customer satisfaction.”

IAV showed a demonstrator with the new climate controller at the ETA Conference in Berlin in December 2016. Work is currently in progress on producing a show car with the new climate control system which will be on display at the Consumer Electronics Show (CES) in early 2018 at Las Vegas.