Around the world people are increasingly suffering from air pollution. In an interview Martin Klein, Vice Pre­si­dent for Cabin Air Fil­tra­ti­on, talks about the fil­ter­ me­dia of the future and intel­li­gen­t cabin filter ­sys­te­ms for elec­tric vehicles.

Professional career

Martin Klein studied process engineering at the Karlsruhe University and since February 2017 has been Vice President Cabin Air Filtration at the location in Himmelkron, Germany. He started his career at MANN+HUMMEL in 2003 as a development engineer for fuel filter media and elements for the automotive aftermarket. In 2010, after projects at the Indian location in Tumkur, he moved to the department Innovation and Corporate Strategy and most recently managed national and international teams there.

Mr. Klein, in your last position, you were working in the department Innovation and Corporate Strategy. How did that prepare you for your new task as Product Champion for cabin air filters?

For the last few years, the activities of my teams were in fact strongly focused on the technology required to enable air pollution control. Our task was the development of new areas of business connected to the cleaning of air. In that respect, there was a large overlap with our colleagues in the area of cabin air filtration. This means that I have already worked intensively with the various requirements and topics. As a Product Champion I now see my task to further promote our ‘Leadership in Filtration’ position for this product group. Through new products and the further development of existing products for the automotive and nonautomotive areas we would like to expand the product segment and increase competitiveness. In this process it is very important for me to motivate people in their tasks, to meet challenges and to try out new ideas.

What are the trends currently driving the development of cabin air filters?

The main driver is air pollution in connection with the increased health awareness of people. Another factor is digitalization: Nowadays, we can check the air quality on the smartphone at any time. This creates transparency which naturally leads to calls for better protection.

Are there different degrees of air pollution worldwide?

Yes. Particularly in Asian conurbations such as Delhi or Beijing, the level of air pollution is extremely high. In Europe, some large cities such as Paris and Stuttgart also have considerable problems. A survey carried out by the World Health Organization (WHO) revealed that 92 percent of the world‘s population lives in areas where the air pollution is above the permissible level. This is an appalling figure which shows that air pollution is a global problem.

What is it that contaminates our air?

This can vary a lot. The discussion often focuses on particulate matter. These are particles which are smaller than 2.5 micrometers, i.e. 20 times smaller than the diameter of a human hair. When we breathe in these particles they enter our lungs and take root there. This can cause respiratory diseases or also lead to cancer. Soot particles even pass through the cell walls to enter the bloodstream and may even root in the brain.

Our answer has to be as varied as the nature of air pollution itself. Our modern filter media reliably retain respirable particles.

Martin Klein, Vice President Cabin Air Filtration

What other pollutants are in the air?

In addition to these solids, there are numerous toxic gases. Attention is particularly drawn to nitrogen dioxide (NO2). The WHO has set a limit of 40 micrograms per cubic meter which is often exceeded around the world. When we drive through a tunnel, the tunnel is full of nitrogen dioxide which can cause severe lung diseases. Further toxic gases in our ambient air are ozone, sulfur compounds and ammonia gas. In addition, there are also volatile organic compounds (VOC) such as formaldehyde, which as a basic material for adhesives and paints is very present. Then there are allergenic substances such as pollen from grasses and blossoms. All of this is the mix which we have to combat.

Which media do you use to filter these different substances?

Our answer has to be as varied as the nature of air pollution itself. Our modern filter media reliably retain respirable particles. We offer these synthetic ultra-fine fiber media with a high separation efficiency, simultaneously low pressure drop and long service life for the filter. We partly enhance the effect of this media by electrostatically charging the fibers.

And how does the filtration of gases work?

We mainly use different types of activated carbon to filter out gaseous contaminants. The carbon surface is characterized by a very fine pore structure which binds gas molecules. Our expertise is based on the ability to combine different activated carbons in a single filter medium. That allows us to exactly fine-tune our filters and reliably retain the various pollutants. This is particularly true in the case of nitrogen dioxide. Here our activated carbon media provide highly effective protection which we validate in field tests and with independent laboratories.

And how does a cabin air filter look like which filters out gases and also retains solids and pollens?

We use so-called combination filters which are made of different layers of filter media. These filters include a layer for particulates, different activated carbon layers and can also be produced with a specially developed biofunctional filter coating. It has been verified that this coating with the natural material of polyphenol can reduce the activity of released allergens and their potential to trigger allergies by up to 98 percent.

How important is the cabin air filter business for MANN+HUMMEL?

The above-mentioned trends make the cabin air filter a very important product for MANN+HUMMEL with an excellent potential for growth. The product is used in cars, trucks, buses, construction and agricultural machinery, and trains. It is used in vehicles with or without combustion engine and can also be used for the filtration of the air in private and commercial buildings.

What developments are there in the field of filter media?

The trend here is towards ever finer filtration. In recent years, the demand for high efficiency particulate air filters (HEPA filters) has risen. These products allow the retention of more than 99.95 percent of all particles. These filters usually find application in clean rooms. In areas with road traffic, they would clog within a short period of time. Therefore, we combine them with a pre-filter to a filter system and fine-tune these to work together.

Is the subject of digitalization important with regard to filtration?

Absolutely! This is why last year we founded the IoT lab in Singapore especially for this purpose. The facility has expertise in the area of sensors and transmission possibilities. This will become more important in future because we can only make our products more intelligent with the use of new technology. HEPA filtration solutions are expensive. The aim must be to only use them when they are actually needed. This in turn gives an advantage to the end consumer. We are currently working on such an energy-efficient, smart cabin air filter system for electric vehicles.

Why choose electric vehicles?

One major challenge for electric vehicles is to maximize their driving range. Therefore, the energy of the battery should be dedicated for driving and not be used for climate control in the interior of the vehicle.
Our intelligent system FreciousSmart allows the air to circulate inside the cabin after it has been heated up once. However, at some point the air does become sticky and damp, and a certain amount of air from the outside is required. The indoor air quality sensor in our system measures the CO2 content, the air humidity and temperature and determines how much outdoor air is actually required. At the same time, another sensor measures the quality of the outside air and only switches on the respectively required filter. This offers constantly maximum protection for the occupants of the vehicle while maximizing the driving range and enabling the longest change interval for the filter.

Energy-efficient, switchable cabin air filter system from MANN+HUMMEL

Interior air filter

HEPA filter

Ambient air filter

Which development stage is the product in now?

We are currently in the concept stage and have already approached different customers with the concept. The feedback was entirely positive. The interaction of filtration know-how, system design and IoT expertise offers unique possibilities for the development of innovative cabin air filter concepts and therefore decisive advantages for our customers. In the next stage, we will test the function, develop the first concepts and validate these.

Which are your target markets?

Currently, our main market is Europe and in particular Germany. But primarily, we see considerable potential in Asia: On the one hand, the large conurbations are trying to combat bad air quality. On the other hand, China especially with its large cities is an important market for electric vehicles. Our task is to strengthen the general awareness that the cabin air filter of the vehicle provides effective protection.

How much are you driving the local production of products?

We have a global R&D and production network. In Fayetteville, Shanghai and Bangalore, we have testing centers for cabin air filters and also engineering and prototype production. This is where the products are also further developed for local markets. There is a regular exchange of information between our engineering teams in the US, India and China and our competence centers in Himmelkron and Marklkofen in Germany. It is very important for me that the locations can work independently. We cannot deal with the growing challenges by managing all our projects centrally. We must remain agile and flexible, manage changes with confidence and at the same time ensure the high quality of our products while making sure we take local requirements into account.

How will cabin air filters develop?

We will continue to further develop our filter media portfolio to meet the increasing demand. We are already in a good position with efficient solutions and are able to cover the full range of cabin air filtration. We want to further develop FreciousSmart and prepare it for series production. In addition, there is an increase in inquiries for integrated systems – ranging from the housing with its associated pipes to control elements and sensors. Our decisive advantage here is that MANN+HUMMEL has extensive experience in designing efficient air cleaner systems for engine air filters, including advanced simulation methods and acoustics. We understand how the components work and have to interact, which enables us to develop optimized integrated filtration solutions. We are a leader in this field.