Automotive Development with a Preserving Jar: The Audi Nose Team Sets Strict Odour Standards

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August 26, 2002

Automotive Development with a Preserving Jar: The Audi Nose Team Sets Strict Odour Standards
Text and Photos courtesy of Audi AG

They stick their noses into everything that concerns them – that’s just part of the job. The Audi odour team, generally referred to as the “nose team”, is on the trail of disagreeable odours in vehicles and ensures a consistently pleasant odour level in Audi vehicles. Plastic parts that give off unpleasant odours, leather that smells like fish oil or floor mats from which the aroma of onions emanates, have no chance at Audi. The same applies to materials that could discharge emissions in the vehicle that are detrimental to health. Around 500 various components from the vehicle interior are analysed per model by the measuring device of the human nose. Audi applies the strictest standards in the fight against odours and is the benchmark in the branch. The aim is in fact not the “odourless” but rather the “neutral odour” car in which the customer feels at ease.

“There cannot and will not be an odour-free car. That isn’t even desirable. You wouldn’t want to sit in a noiseless vehicle either,” explains Heiko Lüßmann-Geiger, graduate chemist and Head of the Audi nose team. The car has come to symbolise an emotional event. “You spend so much time there that sensual perceptions become more important,” states Lüßmann-Geiger. A new vehicle should always therefore have a typical but never unpleasant odour. It is up to the olfactory experts to ensure this. Olfaction relates to the sense of smell.

What in comparison to other vehicle properties plays at first glance a rather subordinate role, has for the customer an unconscious fundamental significance. 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 smell. If the customer is now irritated by this odour from below, he will no longer correctly perceive all the other positive comfort properties of the vehicle. He is too irritated by the stress brought about by the odour.”

The nose team was already an indispensable part of vehicle development and quality assurance at Audi back in 1985. Since then the Ingolstadt car manufacturer has played a pioneering role in the field of vehicle odours. 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 odour assessment.

Until this point in time, almost every vehicle producer had its own system for eradicating unpleasant odours. The Ingolstadt chemists had compared the test parameters and worked out a standard test specification for the odour test. With success: since 1992 this process has been adopted by all German manufacturers. The benefit: The car builders can compare their results in this way and the suppliers only have to have their components further tested by one process.

The five-person core team (three other members are always on call) is made up of three “female” noses and “two” male noses. The team is located within Audi’s quality assurance before the start of production. The odour-sensitive troop has the final say on the suitability of a material for its use in the car. Materials that fall through 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 odour quality of production vehicles. As a result, individual cars are taken at random out of the production runs almost on a daily basis and intensively sniffed in the chemical analysis laboratory. “It can be the case that a supplier after a certain time employs a slightly different material composition or uses another manufacturing process, and suddenly we have odours in the vehicle that are undesirable,” comments Lüßmann-Geiger.

The assessment scale corresponds to the school grades system in Germany, i.e. from 1 to 6. Grade one means “odourless” and a six “unbearable”. Lüßmann-Geiger: “Only materials such as metal, glass, ceramics or stone are evaluated as “odourless”. And from these things alone you cannot build a car.” Everything in the grade range from 1 to 3 passes the strict Audi test, materials given the grades 4 to 6 fail. “The difference between grade three (`strong intrinsic smell, not yet unpleasant’) and four (`irritating’) 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 exhalations can also be seen. Motorists are familiar with the thin lubrication film that condenses after a certain time on the inside of the windscreen. This film is brought about by substances emanating from components in the vehicle’s interior when heated up. Experts call this “fogging” (see next page).

In the normal daily routine, all the team members go their separate ways to work 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 `odour’ and have shown a willingness to quantify a problem to which a figure cannot so easily be attached by the measuring device of the nose,” explains Lüßmann-Geiger.

To be a member of this team also requires certain deprivation as the testers’ sensitivity to odours must be guaranteed at all time. Smokers, for example, would not be considered for the work in the nose team as their olfactory nerves are too numb. State of health also plays a decisive role, especially in the area of the respiratory tracts. A simple cold can make the team member “unfit for work” as even nose sprays or drops cannot help.

And then other personal circumstances can decide 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 changes the perception of the person himself. The same is true of perfumes and after shaves, albeit with a more pleasing scent. Their use before taking part in a test is forbidden.” Even discreet scents, such as in aromatic herbal baths or creams, must be avoided by the Audi noses.

Prepared in this way, members of the nose team meet each day in the Quality Centre of the Audi plant in Ingolstadt to stay hot on the trail of unpleasant odours. The test procedure is carried out as follows: a section is cut out from 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 – really every component, every material that is to be applied to an Audi “comes under the nose”.

These “component specimens” are then placed in a jar with an odourless seal. Lüßmann-Geiger points out: “Normal preserving jars are used for this at Audi, the sort that can be obtained from a hardware store – and that’s where we buy them from.” It sounds simple and it is too: these containers, as well as being good value, are ideal for the odour test as they are absolutely scent-free, “Since when preserving cherries, for example, no other scent may get into the jar.” (Lüßmann-Geiger)
The sealed jar is then heated in an oven at 80 degrees Celsius 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 covertly on a piece of paper. The result is represented by the mean value of all the marks together. “Odour tests cannot be carried out on a piece-work basis though,” states Lüßmann-Geiger. After five or six tests the noses then need a rest for one to two hours before they are again in the position to make an objective evaluation.

Of course, odour analysis at Audi doesn’t just stop at the small specimens. In order to test the interplay of various materials, complete components such as dashboards are inspected in a special cubic-metre large stainless steel heat chamber. The odour test is carried out through a hose connected to the chamber. At the end of the hose there is a glass mask which fits perfectly over the tester’s nose. In this way, no odours from the ambient air can affect the assessment.

The final stage is the assessment of the complete vehicle. The interior of the vehicle is heated with large radiators for this. By way of information: a car standing in the blazing sun can develop interior temperatures of up to 80 degrees Celsius. It is exactly this status that the test tries to recreate. The nose team members then jump quickly into the car, assess the overall impression and try as well to identify parts with a particularly strong odour. “This overall test is necessary to ensure that various inconspicuous odours from components do not create an unpleasant smell in the mix,” says the team leader.

At the end of this intensive series of tests a discreet odour impression is reached. Every part in an Audi has a good, neutral odour. A mix that the well-known “new car smell” gives off with which the customer is familiar. The possibility of consciously giving the vehicles a certain fragrance such as “fresh” or “flowery” – in other words a sort of fragrance design – is not offered by Audi. The head of the nose team also states the reason 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 refuses in principle to add scents to the cars.”

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