Press release

Ingolstadt, 2010-08-11

The Audi Nose Team sets strict odor standards: Using a canning jar to develop cars

  • Pioneer and benchmark in odor analysis
  • On the trail of unpleasant odors in cars
  • Scoring scheme from “odorless” to “unbearable”

They stick their noses into everything – it’s just part of their job. The Audi Odor Team, generally referred to as the “Nose Team,” is on the trail of unpleasant odors in vehicles. They work to ensure a consistently pleasant odor level in Audi vehicles. Plastic parts that give off unpleasant odors, leather that smells like fish oil or floor mats that exude an aroma of onions don’t stand a chance at Audi. The same goes for materials that can give off unhealthy emissions in the car. Around 500 different components from each model’s interior are analyzed using the human nose as a measuring device. Audi applies the strictest standards in its fight against odors and sets the benchmark for the industry. The aim is not actually to achieve the “odorless” car, but rather the “neutral odor” car in which the customer feels at ease.

“There cannot be and never will be an odor-free car. That isn’t even desirable. You wouldn’t want to sit in a noiseless vehicle either,” explains Heiko Lüssmann-Geiger, Head of the Audi Nose Team. These days the car has become an event for the senses. “You spend so much time there now that what your senses perceive in the car has become ever more important,” says Lüssmann-Geiger. A new vehicle should therefore always have a typical but never unpleasant odor. It is up to the olfactory experts to ensure this. Olfactorics is the study of the sense of smell.

Although, at first glance, this plays a rather subordinate role compared to other vehicle properties, it has a fundamental significance in the subconscious of the customer. The head of the Nose Team explains this with the example of the scientifically based comfort hierarchy: “You have to imagine this as a pyramid. At the tip of this hierarchy pyramid is the well-being of the customer, right at the base is the odor. If the customer is now irritated by this odor, he will no longer perceive all the other positive comfort-related properties of the vehicle properly. He is too annoyed by the disagreeable odor.”

The Nose Team became an indispensable part of vehicle development and quality assurance at Audi back in 1985. Since then, the carmaker based in Ingolstadt has played a pioneering role in the field of vehicle odors. Lüssmann-Geiger recalls that on the initiative of Audi, the automotive manufacturers in the German automotive industry association (VDA) sat down in 1991 in order to set up a uniform procedure for odor assessment.

Until this point in time, almost every vehicle producer had its own system for grading odors. The Ingolstadt chemists had compared the test parameters and worked out a standard test specification for the odor test. And the effort has paid off: since 1992 this process has been adopted by all German manufacturers. The benefit lies in the fact that car builders can use this system to compare their results, and suppliers now only have to have their components tested by one process.

The six-person core team (three other members are always on call) is made up two women and four men, along with their sensitive noses. The team operates within Audi’s quality assurance in advance of the start of production.

The odor-sensitive group has the final say on the suitability of a material for its use in the car. Materials that do not pass the Audi noses’ assessment criteria are immediately removed from the procurement list.

An important note: the Nose Team is not only integrated at an early stage in the development of new Audi models, it also monitors the consistently high odor quality of production vehicles. To do this, individual cars are taken out of the production runs on a random basis and given a thorough olfactory examination in the chemical analysis laboratory. “It may be the case that a supplier after a certain time employs a slightly different material composition or uses a different manufacturing process, and suddenly we have odors in the vehicle that are undesirable,” comments Lüssmann-Geiger.

The assessment scale corresponds to the German school grades system, i.e. from 1 to 6. Grade one means “odorless” and six is “unbearable”. Lüssmann-Geiger: “Only materials such as metal, glass, ceramics or stone are graded as odorless. And you can’t build a car from these materials alone.” Everything in the grade range from 1 to 3 passes the strict Audi test, while materials given the grades 4 to 6 fail. “The difference between grade three (strong intrinsic smell, not yet unpleasant) and four (unpleasant) is particularly decisive in the acceptance or rejection of a part,” explains the Nose Team leader. Most of the evaluations range between grades two to four. Incidentally, certain odor emissions can also be seen. Motorists are familiar with the thin greasy film that condenses after a certain time on the inside of the windscreen. This film is brought about by low-volatility substances emanating from components in the vehicle’s interior when heated up. Experts call this “fogging".

In the normal daily routine, all the team members go their separate ways in the materials laboratory of Quality Assurance. Most of them work in chemical analysis. “They have been chosen for the Nose Team because they have a sensitive nose. They are confronted time and again in their daily routine with the problem of ‘odor’ and have shown a willingness to quantify a problem that is hard to express in figures by using their noses as a measuring device,” explains Lüssmann-Geiger.

Being a member of this team also requires certain sacrifices, as the testers’ sensitivity to odors must be guaranteed at all times. Smokers, for example, would not be considered for work in the Nose Team as their sense of smell is dulled. Their state of health, especially of the respiratory tract, also plays a decisive role. A simple cold can make a team member unfit for the job, and even nose sprays or drops don’t help.

Other personal circumstances can also determine whether a team member can or cannot take part in a test. Lüssmann-Geiger names a few examples: “The smell of garlic, for example, disturbs not only the other team members, it also changes the perception of the person himself. More pleasant scents to which the same applies are perfumes and aftershaves. So team members are not allowed to use them before taking part in a test.” Even subtle scents, such as those found in aromatic herbal baths or creams, must be avoided by the Audi Nose Team.

Prepared in this way, members of the Nose Team meet each day in the Quality Center of the Audi plant in Ingolstadt to sniff out unpleasant odors.

The test procedure goes like this: first, a section is cut out of a component. From the cockpit or from the rubber sealing above the wood trims or door trims right up to the leather upholstery of the seats – every single component, every single material that is to be applied to an Audi “comes under the nose.”

These “component specimens” are then placed in a jar with an odorless seal. Lüssmann-Geiger points out: “We use normal canning jars for this at Audi – the sort that can be obtained from a hardware store – and that’s where we buy them.” It sounds simple, and it is. These containers, as well as being good value, are ideal for the odor test as they are absolutely scent-free. “When preserving cherries, for example, no other scent may get into the jar,” Lüssmann-Geiger said.

The sealed jar is then heated in an oven at 80 degrees Celsius (176 degrees Fahrenheit) for two hours. And then the assessment begins. Each tester in turn lifts up the lid slightly, smells briefly in the gap between jar and lid, closes the jar again and passes it quickly to the next nose, so that there is no major temperature difference.

Each tester then makes their assessment secretly on a piece of paper. The final result is the mean value of all the marks. “Odor tests cannot be carried out on a piece-work basis though,” states Lüssmann-Geiger. After five or six tests the team members then need to take a breather for one to two hours before they are again in a position to make an objective evaluation.

Of course, odor analysis at Audi doesn’t just stop with small specimens. In order to test the interaction of various materials, complete components such as dashboards are inspected in a special one cubic-meter large stainless steel heat chamber. The chamber containing the pieces is heated. During the test, the inspectors place their heads into the chamber through a whole and evaluate the smell that surrounds them.

The final stage is the assessment of the complete vehicle. The interior of the vehicle is heated with large heaters for this – after all, a car standing in the blazing sun can in fact develop interior temperatures of up to 80 degrees Celsius (176 degrees Fahrenheit). It is exactly this status that the test tries to recreate. The Nose Team members then jump quickly into the heated car, assess the overall impression and also try to identify parts with a particularly strong odor. “This overall test is necessary to ensure that various inconspicuous odors from components do not create an unpleasant smell when mixed together,” says the team leader.

At the end of this intensive series of tests, a discreet odor impression is reached. Every part in an Audi has a good, neutral odor. A mix that yields the famous “new car smell” that customers are familiar with. Audi intentionally foregoes the use of fragrances designed to give cars a certain fragrance such as “fresh” or “flowery.” The head of the Nose Team explains why: “There is no fragrance that is universally pleasing to all customers. What is very pleasant to one person is perceived as unpleasant by another. Audi therefore strictly forbids the addition of scents to the cars.”

Fogging: the veil on the windshield

What is fogging?
Certain odors are not only detected with the nose, you can also see them. Every motorist is familiar with it: the thin, milky film that forms after a certain amount of time on the inside of the windshield. Experts call this “fogging”. This film can lead to impaired visibility, particularly when the sun is low in the sky and shines through the windshield. The first related complaints came from Sweden, where the sun is often at a low angle over the horizon and, as a result, the murky effect is especially noticeable.

What causes fogging?
Fogging is caused by the emission of low-volatility substances from components in the vehicle interior. Substances escape in minute quantities from these materials when warmed up by the sun. They include, for example, softeners, stabilizers and flame-resistant substances, or oils that are added to the plastics and other non-metallic materials to improve their properties. These substances hardly evaporate under normal circumstances, but small quantities are released if the component reaches a high temperature. The substances then condense immediately on a cold area of the vehicle – in most cases the windshield – and there they form the above-mentioned film. When you pass your finger over the glass, you see greasy traces as the uniform layer of film is destroyed. If you wipe the film away, the cloth that has been used will generally be black. This has nothing to do with the substances, which are colorless, but is made up of dust and dirt that cling to the sticky film. This clinging dirt also impairs visibility through the window.

What does Audi do about it?
More than 20 years ago, Audi began inspecting all materials used for car interiors to discover how much of these low-volatility substances they emit. The parts must not exceed the maximum levels that have been set. In this way, Audi has reduced to a minimum what used to be a clearly visible problem. The problem of vapor emission cannot be completely avoided, however, as such substances are always present in plastics. Technical improvements to materials are being achieved through the use of substances that evaporate even less easily and therefore form even less vapor.

What can motorists do about it?
The greasy film can be removed with off-the-shelf windshield cleaner. Simply wiping with a dry cloth will remove most of the film.


Technology is no match for the nose

So, has the time come to replace the human nose with an electronic substitute for the odor test? The head of the Nose Team, Heiko Lüssmann-Geiger, replies with a smile: “The devices that are available under the name ‘electronic nose’ only actually have one thing in common with the human nose, and that is their name. No electronic nose is capable of grading an odor or judging its quality from the signal that it has detected. That is, in the final analysis, the essential work of the odor tester. And the sensitivity of an electronic nose is much poorer. There is no foreseeable prospect of a machine even coming close to the quality of the human nose. We can therefore say with some confidence that the work of the Nose Team will remain indispensable for maintaining the pleasant odor in an Audi for decades to come.”

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