This is where the truth about a particulate filter comes to light. This is the place where it is possible to unequivocally measure its performance: The plant at Feuerbach, building 785, ground floor, flow test bench. How much soot remains in the filter? What pressure loss does it cause? The obvious features of the equipment used in answering these questions are a long tube with plenty of cables and monitors attached. “The test basically works in the same way as a large air pump,” says Lars Thüner. He shows us a Bosch filter, which was fixed in place, and describes the benefits: “It is more efficient than other models and more cost-effective to manufacture.” This gives Bosch a big advantage.

The crucial factor is the use of a new material. Instead of sintered metal, Thüner and his team have incorporated cordierite. The mineral allows thinner walls and a finer honeycomb structure to be used, which increases the filter surface by nearly two square meters. The greater the area, the more soot is deposited and the less escapes into the air. Thüner is dedicated to finding clean solutions. The opportunity to “do something to improve air quality” was what led the 37-year-old chemist to join Bosch in 2001.

With the particulate filter, one thing led to another. While Thüner modestly talks about “by-products,” any promising development steps are safeguarded by patents. In this case, the project resulted in 20 patent applications and the researcher stresses that “all of our solutions came about through teamwork.” Since November 2006, he has had a new responsibility. The chemist has switched to technical customer support, “because I am also interested in how our developments are implemented by customers.” However, other demands mean he no longer has the opportunity to pursue his natural interest in research and Thüner is “curious to see whether I will miss it.”