MANN+HUMMEL GmbH Hall 8 / C11

Becoming carbon neutral is the ultimate goal for the years to come. By establishing a circular economy and reducing the usage of crude-oil based products, important steps can be made right away. Filter elements are often used only once and disposed after they reached a certain level of pressure drop or change interval. The recycling of such highly contaminated waste is challenging and the reverse logistics difficult, especially in the independent aftermarket. Therefore, the choice of raw materials is especially important to reduce the impact on the environment because the materials are mainly incinerated or land-filled at end of life.

The product carbon footprint can be reduced significantly by using alternative materials from recycled or renewable feedstocks. However, these materials need to fulfil all customer requirements and to pass automotive test standards. Recycled plastics are in the focus of the automotive industry to fulfil upcoming legal requirements, especially the plastic recycling rate of at least 25 % in the “Directive on end-of-life vehicles” of the European Commission. The presentation shows the industrial application of recyclate plastics, renewable feedstock for sealings and filter media resins to air, fuel, oil and cabin air filters.

Since many years gaskets made of polyurethane foam function as sealing between filter elements and their housings. These are usually petrol based 2-component systems composed of MDI (isocyanate component) and polyether polyols (polyol component). But especially for polyols, there are various possibilities to replace basic material crude oil. Polyols based on vegetable oils such as soy bean oil, sunflower oil or corn oil are available. Castor oil is a very capable type of vegetable oil to produce polyurethanes. It is possible to adjust the functionality of castor oil-based polyols by dehydration. It enables the proportionate use of renewable raw materials for the composition of lowly cross linked, flexible products such as sealings. Preserving the required mechanical properties like tensile strength, elongation, hardness and resilience and the resistance against thermal stress, chemicals and ageing challenges the creation of the material.

In addition to the design of the filter element, the filter media itself plays a crucial role in the element's performance. For air and liquid filtration, the media typically consist of a combination of a cellulose-based filtration layer and a suitable resin system. The resin significantly contributes to the media's overall performance providing stability, rigidity, and chemical resistance. Depending on the needs, a phenolic, epoxy or acrylic resin can be used to stabilize the cellulose structure and to add e.g., flame retardant properties; using Bio-based feedstocks or ISCC+ certified materials will lower the carbon footprint significantly.

The presentation shows how these alternative materials can be applied in automotive filtration. The impact on the carbon footprint as well as the reduced usage of crude oil as a resource is assessed. Furthermore, details are provided regarding functional performance and product robustness in comparison to traditional designs and materials.

In recent years, the focus on air quality and its impact on human health has become increasingly prominent. Efficient filtration for vehicle cabins (Cabin Air Filters) is considered as more and more important.

A Smart Cabin Air Filter System has been developed to provide drivers with the best possible protection from pollutants in the car cabin. This system includes up to three different filtration stages: a pre-filter, a HEPA filter and optionally a state-of-the-art cabin air filter in the air conditioning system. Additionally, the system is equipped with particle sensors to measure PM2.5 concentration inside the vehicle and in the ambient air, as well as CO₂ sensors to monitor the CO₂ levels inside the car. These sensors control the proportion of fresh air and the operation of the HEPA filter to achieve the best air quality in the cabin while optimizing energy consumption.

The development of suitable filtration materials for this purpose should not only be based on laboratory tests according to DIN 71 460. Additional field tests are essential to achieve optimum results for the development of efficient particle filtration. Thus, an electric demo car was equipped with such a system to prove its functionality and effectiveness in the field.

Proof-of-concept studies in vehicle air conditioning, especially for comparative tests of suitable filter materials, are strongly dependent on a stable size distribution of the ambient air aerosol in order to ensure comparable conditions for the tests. However, the ambient conditions in road traffic are highly variable, even on the same route and stable weather conditions, which significantly limits comparability.

To build a bridge between standardized laboratory tests with monodisperse aerosol according to DIN 71 460 on filter elements and tests in the air conditioning system or filtration unit of a vehicle in the field, tests with the Smart Cabin Air Filter System were carried out in the vehicle in a climatic chamber. These stationary tests were conducted with simultaneous measurements of PM2.5 and ultrafine particle concentrations.

For this purpose, an artificial aerosol with a similar size distribution compared to the ambient aerosol was generated. Many years of experience from field tests in various driving situations formed the basis for this artificially generated aerosol with a mixture of sodium chloride (NaCl, many very small particles, but hardly any particle mass) and ISO fine dust A2 (high number of larger particles, high particle mass PM2.5 / PM10). The aerosol was supplied into the test chamber ....

Fuel cells are basically considered as a green technology addressing the high demand for a sustainable and climate friendly mobility. Without the use of fossil energy, fuel cells provide electrical energy by the electrochemical reaction of oxygen (O₂) of the environmental air with hydrogen (H₂) of the storage tank in the vehicle yielding pure water as the final product. However, since environmental air comprises a wide variety of different gases, some of them negatively affecting the functional performance and the life time of fuel cell stacks, the incoming air must be selectively filtered before entering the fuel cell stack. Basically, air filtration makes use of adsorbents that capture target gases by physisorption and chemisorption, both depending on environmental influences, like relative humidity (i.e. water molecules), air temperature and gas concentrations. In terms of cathode air filtration, the interplay between temperature, water molecules and gases and their interaction with the adsorbent is poorly understood under long term conditions, but mandatory for developing tailored filtration materials. Especially, gaseous air pollutants, such as ammonia (NH₃) and sulfur dioxide (SO₂), were shown in the past to have a negative impact on the functional integrity and on the life time of fuel cell stacks.
In this study, the gas concentrations of ammonia and of sulfur dioxide as well as the environmental air temperature and relative humidity should be continuously monitored for a long period of time, thereby receiving a sophisticated image of environmental conditions. Therefore, dedicated sensors will be installed into a container that is located in a highly frequented street in Ludwigsburg, Germany. Furthermore, besides detection of environmental conditions, a gas adsorption filter, intended for protection of fuel cell stacks, will be additionally mounted into the same container and the ammonia and sulfur dioxide concentrations after the gas filtration step, i.e. on the downstream side of the filter will be detected in situ as well. The results of this approach will enable...

During the last decades membrane technology has become a key technology in filtration and separation applications. The global water economics and mainly the global drinking water supply is based on efficient membrane processes to ensure clean water for consumption. Industrial separation processes in the food & beverage segment, in chemical processing and in all fields of biotechnology rely upon membrane technology as membrane processes treat value products and molecules with high care compared to other separation technologies. The global transformation to green energy resources requiring new energy supply and storage systems like fuel cells, electrolysis and new battery concepts depends on innovative membrane technology.

This presentation will provide an overview about latest innovations and new applications in membrane technology and about future potentials for enhanced membrane products. New membrane materials and material combinations are enhancing membrane applications with higher efficiency on the one hand and with increased separation selectivity on the other hand compared to current state-of-the-art. Specifically modified membranes become highly selective for separation of single target molecules. Modern coating technologies and multi-component material recipes will enable enhanced membrane applications with high operational robustness and attractive economic potential soon. A lot of these innovations are currently driven by start-ups, which offer an enormous innovation potential for transfer and exploitation into industrial scale.

Apart from increased membrane performance and robustness, sustainability aspects play a significant role in membrane innovations. The term “sustainability” refers to future-oriented membrane applications as well as to membranes produced from sustainable, green materials. New environmentally friendly solvents and polymers offer enhanced market potentials for membranes. The ongoing discussions about PFAS molecules contaminating water are pushing these developments. This is especially valid with respect to ion exchange membranes for energy-related applications.

Additionally to the membrane media themselves, the design of membrane modules is a key aspect for safe and economic membrane processes. New types of membrane modules allow a flexible operation and high cleaning efficiencies. Membranes themselves can be specifically designed for an easy integration into modules considering specific application conditions and providing guarantee for long-term operation.