How Nissan Creates Its Signature “New Car Smell”

So many demands are made on the materials used inside a car – they must last for years, must be easily cleaned, withstand extreme temperatures, etc. – that expecting them to smell this good is a lot to ask.

But those tough demands are why automakers employ people like Tori Keerl, a materials engineer at Nissan’s technical center in Farmington Hills, Michigan. She oversees a team of odor experts who carefully analyze the odors of everything inside vehicles like the Nissan Pathfinder SUV and Frontier pickup. I met her on the floor of the New York Auto Show to talk about smells and put my own nose to the test.

Keerl was first hired as a plastics materials engineer, but, in part because plastics make up the majority of materials inside a non-luxury vehicle, she was soon given overall responsibility for the smell of Nissan vehicles inside.

“Every time we launch a vehicle, we have to smell it,” she said.

While a new model is being developed, Keerl and his team test individual parts of the vehicle, such as steering wheels, seat cushions and visors, before putting them into the vehicle to ensure that they have a pleasant – or at least harmless – smell.

“Then we put them in the vehicle,” she said. “We sit in the vehicle and make sure that when we’re in the driver’s seat and you’re in the back seat, you smell that nice new car smell.”

Tori Keerl tests the smell of components in Nissan vehicles before they put them in the car and, again, in a fully assembled vehicle.

Odors in the front seat can be significantly different from the smells in the back seat, she said. In the front seat, there’s a much wider range of material near the nose. Besides the leather or cloth seats, there are the plastics on the dash and whatever the center storage console is made of. There’s also all the binding materials, wires, and adhesives that hold these things together. In the back, you’re surrounded by much more than seat material. There are seats in front of you, behind you and under you. Then there’s the smell of the carpet underfoot.

Even though all the components of the car have, at this time, been presented before being installed in a prototype vehicle, there are still surprises. As with cooking, certain smells that are very good, even very pleasant, can combine to create hellish funk. Or sometimes there was a smell that somehow had escaped all previous sniffles.

Next, Keerl’s team must begin to investigate. She and her team members are all “certified smellers”. (There is training and certification that involves carefully administered smell identification tests.) They begin their investigation the same way you would try to find a strange smell in your own car. They methodically sniff every inch of the car’s interior until they pinpoint where the offending smell is coming from. Once they have reduced the strange smell, they begin the process of detecting the exact material or combination of materials that is causing it.

Often a surprising unpleasant odor in the fully assembled vehicle is due to a supplier changing some aspect of the manufacturing of a part. In this case, Keerl said it would work with the supplier to find what changed and see if the issue can be resolved.

Because a person’s sense of smell can change over time, even from day to day, professional smellers are routinely recertified with blind olfactory testing. They are provided with unlabeled bottles of different scents and asked to identify each one.

I tried it myself and it was surprisingly difficult. Smelling an odor without seeing where it came from is a bit like seeing your child’s first-grade teacher in the supermarket line. You know you’ve met this person before, but without the normal context, you can’t remember where or how.

I opened my first bottle and smelled something vaguely pleasant and rich. It smelled… of earth. When that word came to mind, I realized I smelled like dirt. It was a box full of dirt. The next bottle smelled somewhat woody. I didn’t realize I smelled like pine shavings, but once Keerl told me, I felt kind of silly. Pine must be one of the most recognizable smells in the world, but without being able to see the wood in front of me, I couldn’t quite place it.

Because attitudes toward odors vary from culture to culture, Keerl’s work focuses on cars aimed at North American customers. Car buyers in Europe and Asia may not like a smell that we find perfectly appealing here. They may not like the “new car smell” that Americans enjoy, preferring to have no smell at all.