In the last ten years, the challenges facing cabin filters have further increased with regard to the fine filtration of particulates, the ever tighter installation space and higher performance requirements and cost pressure. In the second part of my blog –  commemorating the 75th anniversary of the company – I will report on the latest developments. (see also History of Cabin Filters)

Sustainable further development

The requirements for the further development of cabin filters have continued to increase in the last ten years with demands for higher performance in terms of separation efficiency, pressure drop, dust holding capacity, adsorption efficiency and gas storage capacity with a simultaneous high pressure on costs. Today MANN+HUMMEL increasingly uses computer simulations to fine-tune the design of filter media to improve the efficiency of the development process and accelerate the market launch of new media.

In addition to higher performance, further challenges are the ever tighter installation space and the complicated integration of filters in modern vehicles. Due to this MANN+HUMMEL also develops elements with complex geometries including very flexible elements which thanks to flexible and voluminous support frames ensure reliable sealing. This technology enables flat cabin filters which are so bendable that the repair garage is able to fit them over a 90° elbow and also remove them afterwards (see Figure 1 and Figure 2).

Figure 6: A flexible filter element

Figure 7: A filter element with a complex design

Antibacterial and anti-allergenic add-ons for combination filters

Over the years there has also been a trend towards higher performance for combination filters. Initially, development activities focused on the subject of unpleasant odours and corrosive gases. In the meantime, however, the requirement for the filter elements to have an anti‑allergenic effect has become a top priority in the further development of the cabin filter.

According to the reports of the World Health Organisation, allergies are the fourth largest chronic illness in the world and in Germany roughly 20 to 25% of the population suffer from allergies. Pollution caused by particulates particularly endangers the inhabitants of larger cities and industrial locations. The mild climate is also increasing the burden on those suffering from allergies. Depending on the weather situation, in the course of the year there are increasingly fewer periods without airborne pollen.

In cars, the allergenic components contained in pollen, bacteria and other ultra-fine particles trigger allergic reactions with sensitive passengers. The particles penetrate the vehicle interior through the intake of air into the ventilation system or through the air conditioning system and can therefore increase the risk of an accident.

Sneezing incidents while driving are unpleasant and also dangerous. This is because during sneezing the eyes involuntarily close on reflex and as a result the driver will travel blind at a speed of 80 km/h for roughly 22 metres. The best protection against such complaints and road risks is to avoid exposure to the allergens. When driving, an appropriate cabin filter offers noticeable relief.

The new MANN-FILTER FreciousPlus, shown in Figure 3, complements the existing product range and goes one step further. Its particle filter layer separates coarse particles such as dust, pollen, wear particles from tyres and also the smallest, respirable particles such as particulates. The next layer consists of highly efficient activated carbon.

This adsorbs corrosive gases such as SO2, NOx, unpleasant odours and ozone from the air flowing through the ventilation system. An innovative third layer comprising a biofunctional special coating has the effect of being antiallergenic and antimicrobial. This protects the driver and passengers against allergens, bacteria and microscopic fungi. The new cabin filter reduces allergens by more than 90%. The growth of microscopic fungi is reduced by more than 95%.

Figure 3: Design of the Frecious Plus

The new filter layer gets its anti-allergenic function through an innovative polyphenol coating. Polyphenols are natural products with an anti-inflammatory effect and are considered to promote health. They occur in different plants such as green tea, pomegranates and many others and have the ability to bind and therefore neutralise allergens.

Cabin filters are not only in demand for motor cars

Whereas from the 1990s up to approximately 2012 the focus was on motor cars, today MANN+HUMMEL filters in the form of particle or combination filters are no longer restricted to cars, buses and trucks. MANN+HUMMEL has now developed the cabin filter technology to meet the requirements to keep the driver cabins of agricultural machinery free of pesticides.

For example, MANN+HUMMEL also uses its expertise from automotive applications in long‑distance trains and trams or for stationary applications such as fuel cells, fume exhaust systems for industrial kitchens, for the filtration of air for cleanrooms and other segments. This illustrates that in future there will be many application fields which MANN+HUMMEL can penetrate using this technology.

Worldwide, with countless versions and for almost all cars

In Germany, the Himmelkron production location in Upper Franconia, derived from the acquisition in 2008 of Helsa Automotive, has become the leading plant for cabin filters. Today there are also further production plants for cabin filters in Marklkofen (Lower Bavaria), in the Czech Republic, Mexico, the USA, China and India. This enables MANN+HUMMEL to supply its international customers in all the main international markets with products and to produce locally to support customers.

There is a demand for particle filters in the NAFTA region with the USA and Mexico and also in India, whereby China has quickly developed into a strong market for combination filters. Europe is a combination filter market where customers with air conditioning systems can freely choose between different element versions.

The MANN-FILTER product range serves more than 99% of the cars on the road in Europe. Around the world the company has more than 6,500 filter types on offer for more than 90,000 applications. 1,000 R&D specialists ensure the high product quality at the MANN+HUMMEL group which with 166 filed patent applications in 2015 was once again in the top 50 list of companies filing patents in Germany – for the fifth time in succession. In fact MANN+HUMMEL maintains over 3,000 patent applications, patents and utility models and therefore regularly underlines its innovative strength.